There are two variables or pieces of information needed to be able to answer your question with a somewhat accurate estimate, and only YOU know the answer. Without this information people will just be guessing wildly.
1. What kind of gas mileage do you get in city and interstate driving?
2. How much gas is left in your tank when the light comes on?
Take the time to figure these two things out and do the math.
With a little bit of luck and forethought sometime you will be driving by a gas station when the low fuel light comes on. Fill up then. Record the number of gallons needed to fill the tank. Subtract from the fuel tank capacity as stated in the owners manual. You have answered question 2. Someone may have done this for their Versa and can chime in. You could then assume their low fuel light sensor works exactly the same as yours. Probably not a great assumption to make.
If you give a crap about your car you will already know the answer to question 1.
Doing the math:
Gallons left in the tank when the light comes on multiplied by your fuel economy (in mpg) will give you a pretty accurate guess of how many miles you can go with the light on.