Bring a large pot of lightly salted water to a boil. Add pasta and cook until tender but still firm, about 8 minutes. Drain.
Meanwhile, melt 1 tablespoon of butter in a wok or large skillet over medium-high heat. Add chicken pieces; cook and stir until browned. Season with blackened seasoning, and remove the chicken from the wok and set aside.
Melt the remaining butter in the wok over medium-high heat. Add the garlic and onion; cook and stir until fragrant and beginning to brown. Add the green, red and yellow pepper strips, and season with red pepper flakes, curry powder, salt and pepper. Cook and stir until the peppers are hot. Return the chicken to the wok and pour in the spaghetti sauce. Heat through and serve over pasta.