Steve Nash -- I'm NOT Trying to Duck Child Support

Steve Nash is NOT trying to weasel out of paying child support to his ex-wife ... this according to Nash's attorney who tells TMZ accusations to the contrary are "absolute nonsense."

Nash and his lawyer Robert Schwartz just strolled back into a Maricopa County courtroom in AZ ... where they're set to do battle with Steve's ex-wife Alejandra for the 2nd day in their nasty child support war.

As we previously reported, Alejandra believes the Lakers star is trying to block her from moving with their 3 kids from PHX to L.A. because Steve doesn't want to pay child support. As we reported, Nash is not paying child support in Arizona, but if his wife and kids move to California a judge would likely make a significant dent in Nash's wallet.

On his way into court, Steve didn't want to talk about the allegation -- but his lawyer did ... saying, "That is absolute nonsense and it's not accurate at all."

Alejandra arrived to court soon after.

We're told the judge is expected to deliver a ruling in the case by the end of the day.