Best is relative to a lot of things, including, level of income, level of education, amount of time, etc.
For instance, if you have enough money to go to school full time and accelerated program might be the best bet. Then again, if you struggle with classes, no amount of money put away is going to make the ultra-intense accelerated program a good choice. I know your ultimate goal is to become a FNP.
If you can afford not to work, I will say that, since you already have a degree a year-long ABSN would be quickest. Depending on what prereqs you still need, you could have your BSN in a couple of years (likely not less, as you probably have a number of prereqs to take first). At that point you can (hopefully) find a job. There is a reasonable chance your employer may pay for continuing your education, but even if not, a lot of master's programs are going to require experience anyway, so this would be a good option. However, it is significantly more expensive than, say an ADN. Theoretcially you could work as an RN with an AD and then bridge. But, though an employer almost certainly would pay for the bridge, you will be in school longer this way.
Good luck with your choice.