Creamy Chicken Noodle Soup with Rotisserie Chicken

Melt butter with olive oil in a large Dutch oven over medium-high. Add onion, carrots, celery and salt, and cook, stirring often, until vegetables are slightly softened, 6 to 8 minutes. Add flour and stir to coat. Stir in broth and milk and let mixture come to a boil. Add uncooked noodles to boiling mixture. Cover and cook until noodles are al dente, about 8 minutes. Stir in chicken and peas and cook until pasta reaches desired doneness and chicken and peas are warmed through, about 1 to 2 more minutes. Serve immediately.