If using fresh corn, slice kernels off the cob. For extra flavor, char in a dry hot skillet for 3 to 4 minutes. If using frozen, thaw and pat dry.
Whisk together lime juice, olive oil, cumin, salt, pepper, and chili powder in a small bowl.
Dice avocados into half-inch chunks and set aside.
In a large bowl, combine corn, cherry tomatoes, red onion, jalapeño, garlic, and cilantro. Pour dressing over and toss to coat.
Gently fold in diced avocado, keeping chunks intact.
Taste and adjust seasoning with extra salt or lime juice. Serve immediately with tortilla chips.