Following Mexico's offer to act as a go-between to lower tensions between Washington and Managua, Nicaraguan Foreign Minister Miguel D'Escoto arrived here today for high-level talks.

D'Escoto's trip follows that of U.S. Secretary of State Alexander M. Haig Jr., who visited here Monday and Tuesday.

There is no agenda for D'Escoto's meeting today with Foreign Minister Jorge Castaneda, officials here said, but Mexico's talks with Haig and the subject of U.S.-Nicaraguan relations would almost certainly be raised.

Haig's one-hour talk with Mexican President Jose Lopez Portillo Tuesday reportedly was devoted almost exclusively to Nicaragua, which the United States has accused of supplying arms to leftist rebels in El Salvador and moving toward a totalitarian form of government at home.

Several times in recent days the Mexican president has suggested that, because of its close ties with Nicaragua and Cuba as well as Washington, Mexico could serve as a channel of communication to avoid further escalation of the "verbal terrorism" among the disputing sides and to avert punitive actions hinted at by the United States.

But top officials here are understood to be surprised by the "self-serving" interpretation, as one diplomat described it, given to the Mexican offer by the State Department.

In a briefing to the U.S. press, following Haig's visit here, unnamed State Department sources said that Mexico would now raise its own concerns with Managua over the Sandinista government's massive arms buildup and their political course.

Mexico has "no intention to make unilateral representation to Managua about its domestic policies" but wants to promote a dialogue between Managua and Washington , one high Mexican official said.

This week, Haig told the Mexican president that Washington was considering applying "severe measures" against Nicaragua in a matter of weeks if that country would not halt its "totalitarian trend," sources here said.

Even if Washington takes no punitive measures against Nicaragua or Cuba, which it also accuses of assisting leftist insurgencies in Central America, Mexican policy-makers are said to believe that the harsh language of U.S. officials contributes to the dangerous situation in the region and unnecessarily stirs up the always latent anti-American sentiments even among moderates