Cook rigatoni pasta according to package instructions, drain, and reserve ½ cup pasta water.
In a large skillet, heat olive oil and butter over medium-high heat, then add steak tips, seasoning with salt, pepper, paprika, and red pepper flakes, cooking until browned (4-5 minutes).
Remove steak from the skillet and set aside, then add garlic to the same skillet and sauté for 1-2 minutes.
Pour in heavy cream, milk, and Worcestershire sauce, stirring to combine, and bring to a simmer.
Add Parmesan cheese, salt, pepper, Italian seasoning, and nutmeg, stirring until the sauce thickens.
Toss in the cooked rigatoni, adding reserved pasta water to adjust the sauce consistency as needed.
Return steak tips to the skillet, toss everything together, and cook for an additional 2-3 minutes.
Garnish with chopped parsley and serve immediately.