Nute burn does not specifically mean nitrogen lol. Most nutes in excess will not burn the leaves edges like that! Very few elements in excess actually cause a burn at the tips/margins. It's just a common reaction by inexperienced growers, that as soon as they see burning, it's too much nutes. Excess potassium, phosphorus, sulfur and even chlorine (though that's rare), will cause burning at tips or edges, though other/different symptoms would be present as well, depending on which of said elements is in excess. Magensium, calcium, nitrogen, iron, copper, zinc, neither of these in excess will burn the edges/tips of the leaves. Actually, a lack of potassium or sulfur would also cause the tips to burn, and so will a lack of copper or zinc...again, with other symptoms showing as well. Newbies should learn, that burnt tips, more often than not, are not due to overfeeding!