Would a liquid nitrogen loop be possible assuming you could adequately insulate it? i know it would turn to gas, but not if it went through a compressor/cooler making it into a liquid again. so lets say i had unlimited amount of money, would it even be worth doing from a durability standpoint?
Well, to put it bluntly, it's not a practical idea at all. If you are going to be using a vapor compression cycle, there are much better refrigerants that you can use than liquid nitrogen. While technically possible to get refrigeration from ln2 as it evaporates, you would have to put so much energy into cooling it down to sufficiently condense that I wouldn't really consider it. You can buy phase change coolers that use more practical refrigerants off the shelf which will keep your cpu ridiculously cool (i.e. way below 0).
Even before you spend the money on getting the actual refrigeration unit the pump that you use would probably freeze solid in seconds, rendering it basically useless. The worst I would personally do is dry ice and a standard loop, possibly with a coolant with anti-freeze in it. Along with a pump designed for low temps.
possible - yes, if you were to throw enough money and safety measures at it
practical - no. no. no. in every sense of the word, there are better options to be had.