HEAT oil in medium saucepan. Add kielbasa, carrots, onions and peppers; cook until vegetables begin to soften, stirring occasionally. Stir in flour and mustard until well blended.
STIR in broth gradually. Reduce heat to low; simmer 10 min., stirring occasionally.
ADD 1/3 cup of the cheese; cook until completely melted, stirring constantly. Repeat with remaining cheese, adding in two separate batches. (Do not allow chowder to boil.)