So you don't burn any bridges:
Start your resignation letter with "It is with sadness that I tender this letter of resignation," or something similar.
(I'm sure you can find a sample letter in an online search, better than the example here

)
You go on to emphasize all the positive things you've learned/done while at that position.
You state how you appreciate all the chances to learn and the staff who patiently taught you, and how the experience has made you a better nurse, or has opened up opportunities for many unique learning experiences.
You then state that, after due consideration, you have decided to accept a position at another facility.
You thank them again for their support and understanding, as it was a difficult decision, and you will always remember your time spent at the facility.
You wish them well, and then end the letter.
Is that too cheesy???
The following members say Thank You: