Preheat the oven to 325°F (165°C). Grease a 9 x 13-inch baking dish.
Trim and cut 3–4 chicken breasts into bite-sized pieces and season with salt and pepper.
Place 1½ cups cornstarch in one shallow bowl and slightly beaten eggs in a second bowl.
Dredge each piece of chicken first in cornstarch, then dip into the beaten eggs to coat.
Heat 1/4 cup canola oil in a large skillet over medium-high heat. Brown the coated chicken pieces until golden on all sides, working in batches if needed.
Transfer the browned chicken to the prepared baking dish in an even layer.
In a medium bowl, whisk together 1/4 cup soy sauce, 1/4 cup vinegar, 1 tablespoon red chili paste (such as Sriracha), 1 teaspoon minced garlic, 1/4 cup brown sugar, and 1/2 tablespoon cornstarch until smooth.
Pour the sauce over the chicken and toss gently to coat. Scatter the chopped red pepper and 1/4 cup peanuts over the top.
Bake uncovered at 325°F (165°C) for 1 hour, stirring the chicken every 15 minutes so all pieces get coated in the sauce.
Garnish with chopped green onions and serve.
