I have a nurittionist who has suggested I change my total calories depending on whether or not I exercise for that day. Is there a way I can quickly change from one total or another? Maybe have an option I can change that would say something like "exercise day" or "Non-exercise day" since the requirements are different. Thank you.

She probably means eat more on active days, eat less on inactive days - which is the same as netting calories the way MFP tells you :) Good luck :)

That is what you do on MFP isn't it? E. g. If you get 1200 calories a day and don't exercise, then you only get 1200. If you exercise and burn 500, you get those back so you can eat 1700 that day?

if you want it to be a specific number, just add an exercise, any exercise from database or creat your own
for example
they tell you to eat 300kcal more when you work out, create exercise "eating more" and put it for 1 minute 300 kcal