Heat the oven: Position a rack in the upper third of the oven and heat the oven to 450°F. Put a large rimmed sheet pan in the oven while it heats so the pan gets hot.

Put the chicken strips in a large bowl.

Put the sliced red bell pepper, green bell pepper, onion, and zucchini in a second large bowl.

In a small bowl, stir together the chili powder, cumin, and salt.

Drizzle 1 tablespoon of the olive oil over the chicken in the bowl.

Sprinkle about half of the spice mixture over the chicken. Toss until the chicken is evenly coated.

Drizzle the remaining 1 tablespoon olive oil over the vegetables in their bowl.

Sprinkle the remaining spice mixture over the vegetables. Toss until the vegetables are evenly coated.

Carefully remove the hot sheet pan from the oven and set it on the stove. Spread the vegetables on the sheet pan in a mostly even layer.

Put the chicken strips on the sheet pan around and over the vegetables in a single layer as much as you can. Avoid leaving the chicken piled in thick clumps, or it will steam instead of brown.

Roast until the chicken turns opaque on top and the vegetables start to soften, about 10 minutes.

Remove the sheet pan from the oven. Use tongs or a spatula to stir the vegetables and flip the larger chicken pieces so a new side touches the pan.