Yes, you can. The Sims 2 Double Deluxe (Base + University + Nightlife) fully supports custom content (CC) like the standard edition. The compilation does not block CC.
Documents\EA Games\The Sims 2 Double Deluxe\Downloads\~/Documents/Aspyr/The Sims 2 Double Deluxe/Downloads/Downloads folder before mass installs.Double Deluxe = Standard CC support. Enjoy 20+ years of community content!