There aren’t many sure things in basketball, but there are a few. Shooters get paid. Refs get yelled at. And the Nets play nail-biters — more than anybody else in the league. “Now we’ve got to learn how to close out games against really good teams,” DeMarre Carroll told The Post in the aftermath of Tuesday’s 109-108 loss at Oklahoma City. The lead changed six times in the final 2:23, the latest in a string of tooth-and-nail affairs. “We talk about end-of-game scenarios a lot,” Joe Harris said, “where we have these experiences where we’ve been in this situation a lot, and using this experience — especially when playing against high-caliber teams like [Oklahoma City] — is only going to be beneficial for us down the road.” The Nets have seen 22 games decided by six points or fewer, the most in the league, including 10 of the past 12. And for them, six points is a blowout. Tuesday was their fourth game decided by a single point in January alone. There was the 98-97 victory over the Timberwolves on Jan. 3, with the Nets set to play the rematch in Minnesota on Saturday. Then came the 114-113 overtime loss to Toronto on Jan. 8. And Sunday’s 101-100 win in Detroit, before blowing a 15-point third-quarter lead and falling in Oklahoma City.