say you want to change dirk nowitzki into john doe. create a team and name the coach dirk nowitzki. take that team into association mode and export it. load up the roster in which you want the name change and also load up the exported team. go to edit team and change dirk nowitzki to john doe, exit and then you can delete the team. now dirk nowitzki will be john doe.
thats the basics of it. there are some things to keep in mind though. you want to try and use names with equal or more letters in both the first and last names. so say for instance you want to create a guy named john doe you need to use a player with at least 4 letters in the first name and 3 letters in the last name. 2k11 is a little more flexible in this regard, in 2k10 you would end up with random players though out the league with jumbled up names if you strayed from this but strangeness still occurs so try and stick by this rule if you can.
the other thing is if you change a name it is universal, meaning if you change a player like dorrell wright to john doe then brandan wright will brandan doe. or chris richard to john doe then richard jefferson will be doe jefferson.
if you plan on changing multiple players names then there can be quite a bit of thought involved. if you want i can post or pm you a list of players that are good candidates (meaning not so common names that likely wont cause other changes) along with their skin tone and amount of letters in their names. doing this really simplified the decision/searching process for compatible name changes.
one other thing i do is create the team i plan on exporting on a separate roster before taking it into association and exporting and then loading that team on a fresh create a team slot that hasnt had a coach named on it originally.
make sure to keep multiple roster saves during this process since you can run into some strange stuff and may need to go back to a previous save. doing 70+ name changes takes forever, once you have the exported team on file you can use it later for other rosters so name the exported team save as the name you gave the coach to make it easy to re-use or troubleshoot if needed.
after each name change you make, be sure to skim through your entire roster to see if any unwanted changes have occurred. they can be completely random and as i stated in the original post sometimes names get wiped from the commentators database and the only thing you can do to combat this is manually check each player in game by scoring with them after each name change which isnt practical so beware, this is a glitch afterall. getting around the cap limit to me outweighs 5 or 6 players being called by number rather than by name.
if you want to get rid of those stupid nicknames just do this glitch and give the coach the last name of a nickname like "dimes" and then change it to "D". then give dimes to all the players who you dont want to have a nickname.
let me know if you need any more help or advice or maybe if you have a transfer kit i can just upload a mem card save of all the exported teams with coach names i have so far.