Cook the pasta according to package directions in salted boiling water until al dente. Drain and set aside, reserving about half a cup of pasta water.

Cut chicken breasts into bite-sized pieces and toss with 1 tbsp honey, soy sauce, black pepper, and garlic powder. Heat olive oil in a large skillet over medium-high heat, then cook the chicken until golden brown and cooked through, about 5-7 minutes; remove from skillet and set aside.

In the same skillet, melt butter and sauté chopped onion until softened, about 3-4 minutes. Add minced garlic and bell pepper (if using), cooking for another 2 minutes until fragrant.

Pour in chicken broth and the remaining 1 tbsp honey; bring to a simmer. In a small bowl, whisk cornstarch and water to create a slurry, then gradually stir into the simmering sauce until it thickens.

Return the cooked chicken and pasta to the skillet with the sauce. Toss everything together, adding a splash of reserved pasta water if the sauce is too thick.

Garnish with fresh parsley before serving hot.