Preheat oven to 400F.
Wash and dry potatoes. Let dry completely before putting them into a large bowl and coating with avocado oil. Add chimichurri, salt and pepper and mix well.
Spread potatoes evenly on an ungreased baking sheet and bake for 20 min.
While the potatoes are baking, slice cherry tomatoes in half and place in the same bowl that you used for the potatoes. Give them a good stir to pick up any remaining oil and seasonings.
After the potatoes have baked for 20 minutes, remove from oven, spray sheet pan and add tomatoes.
Using a wooden spoon or spatula, spread potatoes and tomatoes to sides of pan to allow room for fish. Place cod filets in the middle of sheet pan and cover with approximately half of the creamy dill sauce (a silicone brush works nicely), reserving the other half to dip the potatoes in when eating.
Bake for 12-14 minutes or until cod easily flakes with a fork. Enjoy!