Cut the chicken into 1-inch pieces, season with salt and pepper, and set it aside.
In a small bowl, mix together garlic powder, onion powder, thyme, rosemary, paprika, and chili powder. Sprinkle half of the seasoning mix over the chicken.
Drizzle ½ tablespoon of olive oil over the chicken, tossing it to coat evenly.
Heat 1 tablespoon of olive oil in a large 12-inch skillet over medium-high heat. Add the chicken and cook for 6 to 8 minutes, turning occasionally, until browned and fully cooked.
Transfer the chicken to a plate, cover, and set aside.
Return the skillet to the stove and heat the remaining olive oil. Add the onions and cook for 2 minutes, then add the broccoli, zucchini, and peppers. If needed, add a little more oil. Season with the rest of the spice mix, along with some salt and pepper, and cook for 4 to 6 minutes, stirring occasionally, until the vegetables are crisp-tender.
Pour in the chicken broth and stir to combine.
Return the cooked chicken and its juices to the skillet, stir everything together, and cook for another minute.
Remove from heat, taste, and adjust seasoning if needed.