Preheat oven to 400°F (200°C). Place a large wire rack on an 18x13-inch baking sheet and spray the rack lightly with nonstick cooking spray.

Pour the 2 cups panko breadcrumbs onto a second baking sheet in a loose mound. Drizzle the 2 Tbsp olive oil over the panko and use your fingertips or a fork to toss until the crumbs are evenly moistened. Spread the panko into an even single layer on that sheet.

Bake the panko in the preheated oven 3–5 minutes, until slightly toasted and golden, tossing once halfway through to promote even toasting. Watch closely so it does not burn.

Remove the toasted panko from the oven. Gather the crumbs into a mound in the center of the baking sheet and add 1 tsp paprika, 1 tsp garlic powder, 3/4 tsp dried thyme, and 1/4 tsp cayenne pepper (optional). Season with salt and freshly ground black pepper to taste. Mix thoroughly with a spatula so the spices are evenly distributed.

In a medium bowl, crack and whisk the 2 large eggs. Season the eggs with salt and freshly ground black pepper to taste and whisk until blended.

Working in batches (about 8–10 pieces at a time), dip the 1-inch chicken cubes into the seasoned egg, letting any excess egg drip off, then transfer the pieces into the seasoned panko. Toss and press the breadcrumbs onto the chicken so they adhere well.

Arrange the coated chicken pieces in a single layer on the prepared wire rack, leaving a little space between pieces for air circulation. Repeat dipping, coating, and arranging with the remaining chicken, scooping the panko back together between batches as needed.

Bake the chicken in the preheated oven until the internal temperature of the largest pieces reaches 165°F (74°C) on an instant-read thermometer, about 15–19 minutes total.

Remove from the oven and serve warm. Offer a dipping sauce if desired.