In a large pot add olive oil and ground sausage. cook until browned. Add chicken broth and bring to boil. Add as many mustard greens as the pot will allow, keep adding more at they wilt until add have been added. Add navy beans, tomatoes, salt and pepper. Cook for 20 min on med-high heat, stirring occasionally, or until greens are thorouly cooked. Remove from heat and stir in parmasean cheese. Serve.