Preheat oven to 400 degrees F and line with paper liners or grease a muffin tin.
In a small bowl, using a fork or your fingers, combine the ingredients for the streusel topping (butter, brown sugar, and flour) until crumbly and pea sized lumps remain. Set aside.
Make the muffins:
In a bowl combine your dry ingredients, flour, sugar, baking powder, cinnamon, nutmeg, and salt.
In another bowl, whisk together the pumpkin, butter, and eggs until combined. Gently add the dry ingredients until just combined, taking care not to over mix (not over-mixing is the secret to a great muffin). Fold in the chocolate chips.
Using a large ice cream scoop, fill each muffin tin about ⅔ full. Sprinkle with streusel topping and pat each gently. Don’t skimp here or you’ll be streusel-less when you pull these babies out of the oven and that just makes me sad.
Slide the muffin tin into the oven and bake for 22-25 minutes, or until a toothpick inserted in the center comes out clean.