My :02:
There are a couple things I'd look at.
Is Giz getting enough exercise? They say a tired dog is a good dog, and nuisance barking could be a sign he's not tired enough.
Another thing I'd look as is establishing a routine. If your dog knows he's going to get walk time at a certain hour, or play time with you at another hour, he's less likely to bark for attention in between.
With my dogs, they eat in morning, take a short break, go for a walk, then have chill time while I go to work. When I get home, I either walk them or play with them or both for about another hour. Then they get more chill time while I relax.
I find the nuisance barking mainly comes when I break the routine -- i.e., I come home from work and don't take them for a walk. When there's no getting around it and I want them to stop, I usually try distracting them with a chew toy.
If you've done everything right and he still barks, it's probably because he's trying to train you.
Ignore it or put him somewhere where they can calm down