President Reagan, in a move that may face a court challenge, yesterday named Washington lawyer Philip Lacovara to the commission that nominates Superior Court judges as a replacement for William A. Borders, who was named to the panel by President Carter.

Borders, who said he was named last year to a five-year term on the seven-member D.C. judicial nomination commission, said last night he has refused to resign and may go to court to keep his seat. "I'm going to talk to my lawyer," he said.

Borders is president of the predominantly black National Bar Association.

Lacovara is a former top member of the Watergate special prosecution force. He resigned that post in 1974 to protest President Ford's pardon of former President Nixon.

Borders said last night that he had been called to the White House and asked to step down, but refused to do so. He said he understood a letter has been sent to his home asking again that he yield his seat.

However, he said, his understanding is that the post is not one in which service is at the pleasure of the president. "If I thought it was, then I would have resigned," he added.

Other members of the nominating commission are appointed by the mayor, the City Council, the D.C. bar association and the chief judge of the U.S. District Court here.

When a vacancy occurs on the Superior Court, the commission has 30 days to recommend three names. The president must appoint one of them.