Just my opinions:
1. Golden Nugget is a dumpy casino located on the renovated Fremont Street. I view their sports betting with a skeptical eye. Not that any of the casinos are exactly honest.
2. I'd suggest sports betting at: Sahara, Boulder Station, Palace Station, Texas Station, Sunset Station, Orleans, Silverton, or Bally's. There's one other but I can't recall the name. I think it was just across the street from Rio.
Just my opinion. Plus the fact I often used to walked out of these places with more money in my pocket than when I walked in so I'm biased.