Vice President Bush, engaging in some friendly arm-twisting, joined a long list of Maryland Republicans yesterday who have urged Howard County Executive J. Hugh Nichols, a lifelong Democrat, to join the GOP.

"He said, 'If you want to tell them, you can tell them the vice president leaned on you,'" said Nichols, 53, who received a surprise telephone call from Bush at 3:25 p.m.

The GOP is attempting to draft Nichols as a candidate for governor in 1986, and the call coincided with a visit to Nichols' Ellicott City government office by state Republican Party Chairman Allen Levey and two members of the Republican National Committee.

Levey presented Nichols with a petition signed by 240 state Republican leaders and a resolution adopted by the Maryland Republican Party urging him to jettison his Democratic affiliation and join their ranks.

"The whole process has been rather humbling. I'm quite honored by it. I just don't want to act precipitously in any way," Nichols said.

Nichols, whose second term as Howard County executive expires in 1986, cannot succeed himself in office. He was the first Democrat to officially open a campaign for governor last March.

But he joined a field that was already crowded by two unofficial candidates, Attorney General Stephen H. Sachs and House Speaker Benjamin L. Cardin (D-Baltimore), and by the rumored entry of a third, Baltimore Mayor William Donald Schaefer.

Of the four men, Nichols was least known around the state. His campaign was greeted with "indifference" from party officials and "lack of attention from the media," he said yesterday.

As a result, he dropped out of the race last month. Republicans began wooing him almost immediately, but Nichols has been reluctant to switch, both out of loyalty and because registered Democrats outnumber Republicans by a 3-to-1 margin in the state.

In yesterday's telephone call, Bush said he wanted to add his voice of encouragement to that of other state Republicans and offered to help with advice and counsel, Nichols said.

"I was pleased that he would take the time and consider Maryland to be important enough to make a call of that nature. I was surprised, too," he said.