In a large bowl, whisk together 1 tablespoon olive oil, cumin, chili powder, garlic powder, salt, and pepper; toss chicken breasts to coat evenly.
Preheat grill to medium-high heat and grill chicken for 6 to 8 minutes per side until internal temperature reaches 165 degrees Fahrenheit (74 degrees Celsius).
Rest chicken for 5 minutes before slicing into 0.5-inch strips.
In a separate bowl, combine cooked rice with chopped cilantro and 1 tablespoon of lime juice.
Prepare avocado salsa by folding together diced avocados, red onion, and the remaining 1 tablespoon of lime juice in a small bowl.
Assemble bowls by dividing the cilantro-lime rice, black beans, corn, and cherry tomatoes equally among four dishes.
Place sliced grilled chicken atop the base and finish with a portion of the avocado salsa.