Preheat oven to 350 degrees F.
Line or grease a muffin tin.
In a large mixing bowl, beat sugar and butter together until light and fluffy.
Beat in eggs and vanilla.
In a separate bowl, thoroughly mash the bananas.
Fold the bananas into the sugar mixture.
In a separate mixing bowl, whisk the flour, baking soda, and salt together, until thoroughly combined.
Using a spatula, gently mix the flour mixture into the sugar mixture.
Gently fold in the walnuts and chocolate chunks.
Pour mixture into prepared muffin tin, filling just over 2/3s full.
Allow batter to sit in the tin for 20 minutes before placing in the oven.
Bake for 18-20 minutes or until just beginning to go brown on the top.