Preheat the grill. Brush the corn with butter, then sprinkle evenly with 1 teaspoon cumin. Grill about 5 minutes, turning throughout, until corn starts to char slightly. Remove from grill and use a sharp knife to cut off the kernels. Discard cob and seta side kernels.
Pit your avocados and place avocado "meat" in a medium bowl. Mash with a fork until creamy but still has some texture. Add lime juice, cilantro, garlic powder, chili powder and mix to combine. Season with salt and pepper to taste. Gently stir in tomatoes, onions, and corn. Serve immediately.
Serve with chips for dipping, or as a topping for your favorite Mexican dishes like enchiladas, tacos, burritos, salads and more!