Line a large sheetpan with foil and spray with Pam or other cooking spray.
Trim excess fat from boneless skinless chicken thighs and cut into large chunks (halves or quarters).
Peel and chop the two sweet potatoes into bite size pieces.
Cut bell peppers into bite size pieces.
Drain and rinse the can of chick peas.
Stir together 2 tablespoons of vegetable oil, 1/2 tsp of cumin, 1/4 tsp of ground coriander, 1/4 tsp of salt, 1/4 tsp of cayenne pepper in a large bowl. Add sweet potatoes, bell peppers, and chick peas to the bowl and toss to coat the vegetables with the seasonings. Transfer veggies to the sheetpan.
In the same bowl, without rinsing, add the last 2 Tbsp of vegetable oil and the taco seasoning. Add the chicken and stir to coat with the taco seasoning. Add the chicken to the sheetpan, spacing evenly.