Preheat oven to 350℉. Spray a 13x9-inch baking dish with cooking spray.
In a small saucepan, combine caramels with cream, and heat on low, stirring constantly until thoroughly melted and combined. Remove from heat and set aside.
In a large bowl, mix flour, oats, brown sugar, baking soda, and salt. Add melted butter, and beat on medium speed with an electric mixer until thoroughly combined.
Press half the dough in baking dish, and bake 8-10 minutes, Pour most of the caramel mixture evenly over the base, reserving a small amount. Spread chocolate chips evenly over caramel. Sprinkle with nuts, if desired.
Crumble remaining dough evenly over top of bars. Bake 12-15 minutes longer.
Remove from oven, and drizzle with reserved caramel. Refrigerate at least 2 hours before cutting to serve.