Preheat your grill to medium-high heat.

In a bowl, combine the cubed sweet potatoes, sliced yellow squash, olive oil, garlic powder, paprika, dried thyme, salt, and pepper. Toss until the vegetables are well coated with the seasoning.

Place the seasoned sweet potatoes and yellow squash on a baking sheet and spread them out in a single layer.

Roast the sweet potatoes and yellow squash in the preheated oven at 400°F (200°C) for about 25-30 minutes, or until they are golden brown and tender.

While the sweet potatoes and yellow squash are roasting, season the chicken breasts with salt and pepper.

Grill the chicken breasts on the preheated grill for about 6-8 minutes per side, or until they reach an internal temperature of 165°F (74°C).

Remove the chicken breasts from the grill and let them rest for a few minutes before slicing.