How do I start a process with a nice value of -20 and not give it root privilege?

I would like to start a process with a nice value of -20. This requires me to use a command like

sudo nice -n -20 matlab

However, this starts matlab as root too. Is there a way to have matlab as non-root? My current approach is

sudo nice -n -20 sudo -u myusername matlab

which to me looks like a hack. Is there a direct approach to do this?