This will vary depending on your equipment and if the games are available in HD. Not all games are provided to DIRECTV in HD.
NBA LEAGUE PASS games are broadcast on Channels 750-768. HD games are represented by a "-1". For example, if the Celtics vs. Lakers game is broadcast in SD on Channel 765, you can see it in HD (if available) on Channel 765-1.
To access DIRECTV HD programming, HD equipment is required. The number of HD channels you receive is based on your package selection.