President Carter was called upon yesterday to come up with a nominee for chairman of the National Endowment for the Arts before Nancy Hanks' current term in that job ends Oct. 1.

The statement came from a principal advocacy group for state and local arts councils, arts organizations and artists, the Associated Councils of the Arts, The ACA also announced a change of name for itself; from now on it will be the American Council for the Arts.

The ACA chairman, pollster Louis Harris, told a press conference here that "delay will be taken as a sign of indecision and indecision can well mean a signal that the arts have slipped in priority."

The President is also being pushed by congressional leaders concerned with arts policy to make a nomination in time for confirmation before Congresss goes into recess in October. Otherwise confirmation would have to be delayed until the next session, probably in March.

Harris also asked the President to set up an office of cultural affairs on the White House staff. He noted that responsibility for cultural affairs in the Executive Office is now spread among several persons. An official with sole responsibility for the arts, said Harris, "if armed with an executive order and with access to the President, could have a major effect on seeing to it that the needs and the full potential of the arts and understood and realized by the federal government."

Asked to distinguish between the Endowment chairman's role and the job of any such White House cultural figure, Harris said that the Endowment's job is to deal with the "cultural constituency" of the country. A White House person would be entrusted with responsibility for monitoring and managing cultural affairs within the federal bureaucracy. Performance of government agencies in the interests of the arts is erractic, he said, and "we need a front and center person at the White House" to solve the problem.

Concern that the Arts Endowment chairmanship be filled promptly is no doubt aggravated by the six-month hiatus this year at the Humanities Endowment between the resignation of Ronald Berman at the end of his term and the appointment of Joseph D. Duffey to fill the job. But Hanks, who has served as Arts Endowment chairman for two terms and might be renominated, is believed to be willing to continue on if a candidate is not chosen by October.