I was just wanting to find out if there is a lot of work involved in converting a 93 sentra from automatic to manual. Is it somthing to take to a pro?

lots of work...yes
you can do it if you know your way around a car, but it takes a lot.
if you can replace a transmission, clutch, flywheel, clutch master cylinder, slave cylinder(i believe its a hydraulic clutch), brake and clutch pedal, drill through the firewall for the CMC, and other stuff, then thats kind of what it takes