Easy Sheet Pan Chicken Fajitas with Cheese

Estimated Yield: 4 dinner portions | Serving Size: ¼ of the filling | Total Servings: 4

• 1.7 pounds chicken tenderloins, cut into strips about ½ inch thick and 2–3 inches long: Similar-sized pieces cook more evenly. Substitute the same weight of boneless, skinless chicken breasts, cut to the same thickness.

• 3 medium bell peppers, one each red, green, and yellow, cut into ¼-inch strips: These add color and sweetness. Any mix of colors works; use about 360 grams total after trimming.

• 1 medium red onion, cut into ¼-inch strips: Adds flavor and softens as it roasts. Substitute a yellow onion of similar size, about 110 grams after trimming.

• 2 tablespoons olive oil: Coats the filling and helps spread the seasoning. Use the same amount of avocado oil instead.

• 2 tablespoons fajita seasoning: Adds the spice blend without measuring individual spices. Taco seasoning also works, though its flavor and salt level may differ.

• 1 cup (4 ounces) shredded Monterey Jack cheese: Melts over the filling. Substitute the same weight of mild cheddar or a cheddar-Jack blend.

• 8 small flour or corn tortillas, for serving: Start with two per person, serving any extra filling alongside. Warm them according to the package directions. Optional toppings include sliced avocado, plain Greek yogurt, mango pico de gallo, and cilantro.

Yes. Measure 2 tablespoons rather than assuming every packet contains the same amount. This recipe’s nutrition estimate uses Siete chicken fajita seasoning. Salt levels vary by brand, so leave out extra salt when using a salted blend. Add the seasoning dry; this oven method does not need the water listed in some skillet directions.

Use two unlined 13 × 18-inch rimmed metal sheet pans for this batch. Divide the filling evenly, keeping the chicken pieces from overlapping and leaving small gaps throughout. Place oven racks in the upper and lower thirds. Switch the pans between racks halfway through roasting and turn them front to back. Shallow metal pans let moisture escape more easily than a deep baking dish.

Required Equipment: Two 13 × 18-inch rimmed metal sheet pans, large bowl, cutting board, knife, measuring spoons, tongs, and instant-read thermometer.

1. Prepare: Heat the oven to 425°F with racks in the upper and lower thirds. Set out both unlined sheet pans. Start preheating before slicing; allow extra time if your oven is still heating.
2. Slice: Dry the washed peppers, then slice the peppers and cut the onion into ¼-inch strips. On a separate board, or after preparing the vegetables, pat the chicken dry and cut it into strips about ½ inch thick and 2–3 inches long.
3. Season: Toss the chicken and vegetables with 2 tablespoons olive oil and 2 tablespoons fajita seasoning until coated.
4. Spread: Divide the mixture between the pans in a single layer. Keep chicken pieces from overlapping.
5. Roast: Bake for about 15–20 minutes, stirring and switching the pans between racks halfway through. Start checking at 15 minutes; the thickest chicken pieces must reach 165°F, and the peppers should be tender. When chicken finishes before the vegetables, move it to a clean plate and return it before adding cheese.
6. Melt: Sprinkle ½ cup cheese over each pan. Return to the oven for about 2–5 minutes, just until melted.
7. Serve: Spoon the filling into warmed tortillas and add your toppings.

Allow about 32–40 minutes total. Cooking times are estimates, and oven preheating may take extra time. Continue roasting as needed before adding the cheese.

Add the cheese once the chicken reaches 165°F and the peppers are tender. A light, even layer melts more quickly than thick piles. Return the pans to the 425°F oven just until the shreds melt together. You don’t need a browned crust; waiting for one adds cooking time and can dry out the chicken.

• Watery filling: Dry the vegetables after washing and pat the chicken dry before seasoning. Keep salsa and mango pico off the pans until serving.

• Chicken finishes first: Move cooked chicken to a clean plate and loosely cover it while the vegetables finish roasting. Return it to the pans before adding cheese.

• Uneven cooking: Check chicken on both pans, including thicker pieces. One pan may finish first, so remove each as it becomes ready.

Add fresh toppings after baking so they keep their texture.

Serving option	What to add
Warm flour or corn tortillas	Avocado, plain Greek yogurt, and cilantro
Sweet and savory fajitas	A spoonful of mango pico de gallo
Rice bowls	Cooked rice, cheesy filling, and salsa

Use a slotted spoon for juicy pico to keep tortillas from getting soggy. Tortillas, rice, and toppings are separate from the filling’s nutrition estimate.

Make ahead: Slice the chicken and vegetables the day before cooking and refrigerate them separately at 40°F (4°C) or below. Keep raw chicken sealed on the bottom shelf and remember that preparing the chicken ahead does not extend its storage life.

Refrigeration: Refrigerate cooked filling in shallow containers within 2 hours, or 1 hour when temperatures exceed 90°F (32°C). Keep at 40°F (4°C) or below and use within 3–4 days.

Freezing: Freeze in airtight portions for up to 3 months for best quality. Thaw in the refrigerator; the peppers will soften after freezing.

Reheating: Warm in a covered skillet over medium-low heat or microwave in short bursts, stirring between each. Check that the filling reaches 165°F (74°C) throughout.

Spoilage indicators: Discard filling with mold, a sour smell, or a slimy feel. Follow storage limits even when it looks and smells fine.

Keep separate: Store tortillas and fresh toppings separately from the filling. Assemble just before eating.

Estimates are for ¼ of the filling only, including all the oil and cheese. Tortillas and toppings are excluded.

The calculation uses about 360 grams of trimmed peppers, 110 grams of onion, Siete chicken fajita seasoning, and representative raw chicken-breast data as a proxy for chicken tenderloins.

Nutrient	Estimated amount per serving
Calories	430 kcal
Protein	51 g
Total fat	21 g
Fiber	2 g
Net carbs	8 g

Net carbs means total carbohydrates minus fiber. Nutrition is estimated for one-quarter of the filling. Ingredient brands, vegetable sizes, and portions can change the totals. Chicken supplies most of the protein, while cheese and oil supply most of the fat.

Can I use chicken breasts instead of tenderloins?

Yes. Use 1.7 pounds of boneless, skinless chicken breasts, cut into strips about ½ inch thick and 2–3 inches long. Check the thickest pieces with a thermometer.

Do I need to marinate sheet pan chicken fajitas?

No. Toss the chicken and vegetables with oil and seasoning, spread them across the pans, and bake right away.

Can I use frozen peppers and onions?

Fresh vegetables work best for this method. Frozen vegetables release more water and soften more, so they won’t give the same texture.

Can I double this recipe?

Yes, but double the pan space too. Cook in batches rather than crowding four pans into an oven that cannot hold them with space for airflow.

Can I make these fajitas without cheese?

Yes. Skip the cheese and its melting time. Serve when the chicken reaches 165°F and the peppers are tender.

Even chicken strips, room on the pans, and a short cheese finish help this dinner cook evenly. Warm the tortillas, set out your favorite toppings, and serve while the cheese is melted.