Cook spaghetti according to package directions.  Heat a skillet over medium high heat and add olive oil. Cube chicken and add to a skillet. Cook until no longer pink.  Chop carrots, green pepper, and garlic and add to the skillet. Cook until tender. 

In a small saucepan, make your white sauce by melting 2 tablespoons of butter over medium-low heat.  Add 2 tablespoons of flour and sitr until combined.  Add the milk slowly, 1/2 cup at a time, getting the sauce to thicken by stirring in each half cup of milk.  After sauce is creamy, combine vegetables, chicken, and sauce to the cooked noodles.

Serve with fresh orange wedges.