How do you reach Nirvana when you are craving Nirvana? They say once you reach Nirvana you remove craving. However, don't we need to crave the state of Nirvana in order to reach it? Doesn't that contradict everything an enlightened person who reached Nirvana stands for? Because in order to continue this state, meditation and other things need to be constantly practiced which is a sort of craving in itself.
You do not need to crave Nirvana to reach it. 

Nirvana is present in every moment. The belief that you need craving to observe Nirvana is contradictory because it is incorrect. 

Since it is always present, there is no prerequisite to observe it. This is how spontaneous enlightenment is possible. 

Because it is present in every moment, there is no maintaining that needs to be done. 

The reason the Buddha created his teachings was to combat craving. Craving is what distracts us from observing Nirvana in every moment. That's why he teaches non-attachment. It is only through uninterpreted experience that the illusory separate self and Nirvana can be seen clearly.