The sportsbooks will perform an analysis of each team’s strengths and weaknesses before a season begins. They will calculate the chances of them winning the NBA Championship, the Western Conference, the Eastern Conference and so on, and assign odds accordingly. You will see a favorite and the odds grow progressively longer until you reach the rank outsider.
For example, the LA Clippers were the +325 favorites to win the championship ahead of the 2019/20 season, while the Phoenix Suns were the +30000 outsiders. If you see an NBA line starting with a plus sign, it tells you the profit you stand to make from a successful $100 wager. A $100 bet on the Clippers would net you a $325 profit in that example, whereas a $100 bet on the Suns would earn you a $30,000 profit.
You will also see futures odds on markets like MVP and Rookie of the Year, plus basketball odds on how many wins each team will secure over the course of the season. All of these NBA odds and lines change over the course of the season depending on how each team and player performs.