Bring a large pot of lightly salted water to a boil; add penne and cook, stirring occasionally, until tender yet firm to the bite, about 11 minutes. Drain and return pasta to the pot.

Heat oil in a large, deep skillet over medium-high heat. Saute onion in hot oil until slightly softened, 3 to 5 minutes. Stir red bell pepper and garlic into onion; saute until fragrant and softened, another 3 to 5 minutes.

Stir chicken, green enchilada sauce, red enchilada sauce, diced green chiles, chili powder, cumin, and salt into onion mixture; bring to a simmer, reduce heat to low, and simmer until flavors blend, 8 to 10 minutes. Add Colby-Jack cheese and stir until melted and heated through, 1 to 3 minutes.

Reduce heat to low and stir sour cream into enchilada mixture; cook and stir until heated through. Pour enchilada mixture over penne pasta and toss to coat completely.