"notwithstanding" is a preposition whose object is the noun phrase "the great work you have done". "nevertheless" is an adverb; it cannot modify a noun or noun phrase, or take a noun phrase as an object. This would be correct: There is no chance of you getting the promotion after only two months working here.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.