Prep the chicken: If using large breasts, slice them horizontally to make cutlets about 1/2 inch thick.
Pat dry. Season lightly with salt and pepper.
Set up breading: In one shallow bowl, beat the egg. In another bowl, mix panko, 2 tablespoons Parmesan, Italian seasoning, garlic powder, onion powder, 1/2 teaspoon salt, and pepper.
Bread lightly: Dip each cutlet into egg, let excess drip off, then press into the panko mixture to coat both sides.
Set on a plate.
Sear for crisp edges: Heat 1 tablespoon olive oil in a large nonstick skillet over medium to medium-high. Cook cutlets 3–4 minutes per side until golden and 160–165°F inside. Add the second tablespoon of oil as needed for remaining pieces.
Work in batches to avoid crowding.
Add sauce and cheese: Reduce heat to low. Spoon marinara around and over the chicken (you may not need all 2 cups). Sprinkle mozzarella and the remaining Parmesan on top.
Cover the skillet for 2–3 minutes, until the cheese melts and the sauce is hot.
Build the base: In bowls, add a scoop of grains or zucchini noodles and a handful of greens. Toss with a splash of balsamic or a squeeze of lemon and a pinch of salt for brightness.
Assemble the bowls: Top each bowl with a chicken cutlet, spoonful of sauce, and melty cheese. Add cherry tomatoes and cucumber.
Finish with basil and a pinch of red pepper flakes if you like heat.
Taste and adjust: Add a final squeeze of lemon, a drizzle of olive oil, or a sprinkle of salt to balance the flavors.