"Not a big deal, really"
Translation:Ikke en stor sak, egentlig
'virkelig' would be closer to 'truly' or 'real'
What part of 'really' makes you think that it doesn't have anything to do with 'real'? That's like saying 'true' has nothing to do with 'truly'. Or 'actually' has nothing to do with 'actual'.
If you want to reject 'virkelig', you really ought to change the English sentence to, "Not a big deal, actually."