Would 3 weeks off work as a nurse be long enough to recover from breast lift with augmentation?

3 weeks may be pushing it for your job description. These incisions are under great tension. And any sudden movements may separate the incision, even with the best of closure techniques. The wound strength may need a few more weeks to maximize the result. 

Your plastic surgeon will most certainly always be your number one resource when it comes to returning to your specific
occupation and or activities. With an augmentation-mastopexy I typically do not
want my patients doing any heavy lifting for 6 weeks to ensure that healing is adequate.
I might suggest to someone in your occupation to go back to work on modified
duties.