To be a monk in our church, you must be beyond a novice. There was a time when this wasn't the case, but we are beyond that time in our history, you can't apply the rule of the desert fathers to modern novices.
If Brother Nathanael is a monk, then tell me, who is his spiritual father? Who is his abbot? And most importantly, if Brother Nathanael is Orthodox, who is his Bishop? He needs to be under the obedience of a Bishop, otherwise he most certainly is not Orthodox.
As for his teachings, he's a crackpot with crackpot theories. His New World Order, grand Zionist plan, Freemasonry bull is just plain stupid. He's not a holy fool despite any attempts to appear as such.