First, we need to brine the chicken tenders. Add water and brine spices to a medium bowl and stir to combine. Add chicken tenders and make sure they are submerged in brine. Cover bowl with plastic wrap and set in refrigerator for at at least 1 hour and no more than 8 hours.
Once chicken is done brining, prepare the oil for frying. Place 2-3 cups of oil into a cast-iron skillet (should fill skillet halfway). Heat over medium heat. The oil should take about 7-10 minutes to get to 300 degrees. Use a candy thermometer to monitor temp.
While oil gets hot, prepare the dredge. Mix wet batter in a medium bowl and the seasoned flour into another shallow bowl. Remove tenders from brine and place them on a plate lined with paper towels. Cover with more paper towels so the chicken tenders dry as much as possible.
Dip each tender into flour, then wet batter, and then flour again. Squeeze the tender into the flour to help the flour adhere and create "chunks" of batter that will make the tenders super crispy.
Once oil is at 300 degrees, place a tenderloin into oil. Add 3 more tenderloins and cook all 4 tenderloins for 3 minutes. Flip and cook for 2 more minutes. Remove from oil and drain on wire rack over a baking sheet. Repeat with remaining tenderloins. Let tenderloins cool on wire rack. Raise oil temperature to 350 degrees.
Once oil temp is at 350 degrees, fry chicken tenders again but just for 2 minutes to get them golden brown and extra crispy. Remove from oil and drain on wire rack.