Slice each avocado in half and remove the pits. Use a spoon to scoop out some flesh from each half to enlarge the cavity; reserve the scooped avocado and dice it for later.
Squeeze the lime juice over all avocado halves to prevent browning and set them aside cut-side up.
Heat a medium skillet over medium-high heat and coat lightly with cooking spray.
Add the ground turkey, diced onion, garlic powder, cumin, kosher salt, chili powder, and oregano to the hot skillet. Cook, breaking up the meat with a spoon, about 5 minutes until the turkey is no longer pink.
Stir in the tomato sauce and 2 tablespoons water, then continue cooking and stirring until the sauce is absorbed and the turkey is cooked through, about 6 to 8 minutes. Remove from heat.
Spoon the turkey mixture into each avocado half. Top each with shredded Mexican cheese, the reserved diced avocado, and diced cherry tomatoes.
Serve immediately with sour cream or Greek yogurt on top if desired, and eat with a spoon.