Heat a large skillet over medium-high heat. Add panko and thyme to pan; cook 2 minutes or until golden brown, shaking pan frequently. Combine panko mixture, salt, and pepper in a shallow dish. Place flour in another shallow dish. Combine 2 tablespoons water and egg in another shallow dish. Dredge fish in flour mixture. Dip in egg mixture, and dredge in panko mixture. Arrange fish in a single layer on a baking sheet coated with cooking spray. Bake fish at 400° for 12 minutes or until done.
Combine mayonnaise and remaining ingredients in a bowl; serve with nuggets.
Fun and delicious. We used chipotle flavored panko to spice things up and also subbed pickled jalapenos for the dill pickle in the tartar sauce. It took WAY more than 1 cup of panko to coat just over a lb of fish nuggets, though - I don't think they were light anymore by the time I was finished!