In a large mixing bowl, combine rolled oats, peanut butter, honey (or maple syrup), salt, and vanilla extract. Stir until all ingredients are well mixed and form a thick, sticky mixture.
Fold in the chocolate chips until evenly distributed throughout the mixture.
Line a muffin tin with paper liners or lightly grease it.
Using a spoon or cookie scoop, portion the mixture into the muffin tin, pressing down firmly to create compact cups.
Refrigerate the cups for at least 30 minutes to set.
Once set, remove the cups from the muffin tin and store them in an airtight container in the refrigerator.