Preheat oven to 350 degrees F. Grease an 9x13 baking dish with cooking spray; set aside.

In a large mixing bowl or stand mixer, mix the granulated sugar, brown sugar and eggs together, until combined. Add the salt, vanilla, peanut butter, and butter. Mix until creamy and combined. Mix in the baking soda and oatmeal. Stir in chocolate chips; mix well.

Place batter in the baking dish and spread into an even layer. Sprinkle the M&M's all over the top, then press down slightly, pushing them into the dough a little.

Bake 20-25 minutes until the edges are a golden brown and dough is set.

Place the pan on the stove and let the bars cool completely, then slice and serve.