Cook the Italian sausages in a skillet over high heat, until lightly brown, about 3 minutes on each side. Discard excess grease.
Combine Alfredo sauce, milk, and habanero pepper in the same skillet. Cook over medium heat until bubbly, about 10 minutes. Reduce heat to a simmer and add 1/2 cup pepper Jack cheese. Cover and cook sauce until thickened, about 10 minutes.
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.
Pour sauce over pasta; garnish with remaining pepper Jack cheese, diced tomatoes, and green onions.