What ROM?
I guess you must have the DarkTremor a2sd script, or one based on it, for that command to do anything. It should just move your dalvik cache to internal storage - that shouldn't stop you booting, unless there's some problem like not enough space to actually move it.
Give it a few minutes. If it's not booted after 15 or so, pull the battery, go into recovery and try wiping the dalvik cache. If that doesn't work, back into recovery, wipe dalvik cache then flash the ROM again - no need to do a factory reset. That should set the a2sd script back to its original state, and hence undo the "nocache" command.
I guess you must have the DarkTremor a2sd script, or one based on it, for that command to do anything. It should just move your dalvik cache to internal storage - that shouldn't stop you booting, unless there's some problem like not enough space to actually move it.
Give it a few minutes. If it's not booted after 15 or so, pull the battery, go into recovery and try wiping the dalvik cache. If that doesn't work, back into recovery, wipe dalvik cache then flash the ROM again - no need to do a factory reset. That should set the a2sd script back to its original state, and hence undo the "nocache" command.