I haven't kept a gold nugget, but have kept many other L-number plecos in the discus tank. I find that plecos do not feed on discus slime if they have enough to eat. With a barebottom tank, I can pump in a lot of food and clean out the leftovers very efficiently. These tanks have hardscapes to give plecos plenty of room to hide, but crud is readily accessible. I couldn't keep a planted tank this clean.
My hesitation with a gold nugget is that it grows to 12"+ and can be very disruptive. I keep L-333, L-398, L-262 and others that grow between 4" - 6" max.