Cut the chicken breast into even, bite-sized cubes so every nugget cooks at the same rate. Pat the pieces dry with a paper towel first, since this helps the egg wash cling better later. Season generously with salt and pepper before you start breading anything.
Beat the eggs in one bowl and pour the panko into a second, shallow bowl or plate. Dip each chicken cube into the egg, letting the excess drip off, then press it firmly into the panko. Make sure every side gets an even, light coating before moving to the next piece.
Preheat your oven to 375°F and line a baking sheet with parchment paper. Arrange the breaded nuggets in a single layer, leaving a little space between each piece. Bake for 12 to 15 minutes, flipping halfway through so both sides turn golden brown.
While the nuggets bake, whisk honey, soy sauce, garlic, chili sauce, water, and cornstarch together in a small saucepan. Cook over medium-low heat, stirring often, until the mixture turns glossy and coats the back of a spoon. This only takes three to four minutes, so stay close to the stove.
Once the nuggets come out of the oven golden and crisp, transfer them straight to a large bowl. Pour the warm sauce over the top and toss gently so every piece gets coated evenly. Garnish with sesame seeds and scallions right before you bring it to the table.