In my experience, always, but how you get round it will depend on your exact requirements.
First remember it's 7 levels of nesting, not 7 IF statements. So if you are trying to find a preselected square on a chessboard. Is it A1?, is it A2? is it A3? etc isn't going to work. However, is it in the top half?, is it on the right hand side? , is it in the top half?, is it on the right hand side?, is it in the top half?, is it on the right hand side? will get you down to one square after only six questions. You can write an excel statement to mimic this operation which will use many more IF statements than six but any path taken in the formula will only encounter six so that's OK.
Another more pedestrian way is to write lots of formulae each one depending on the previous one. The first one can deal with 7 discrete values. The next on only operates if the first failed to find a value and carries on for the next 6 discrete values. You can keep on writing these "working" formulae for as long as it takes. If you've written the formulae correctly then one and only one formula will bring back a result. A final result column will assemble the correct answer from the "working" columns.
There are other ways round this sort of problem using lookup tables, modulus arithmetic etc. Your particular problem may need something different or a bit out of the usual. If the above isn't clear some more information on your particular problem might help.