Conrad said he would want to hear how Nussle, a former House Budget Committee chairman, will resolve contentious budget issues.
Conrad noted that five senators, some of whom worked with Nussle in the House, have approached him to express their concern with the way Nussle operates, namely that he is too aggressive.
While Republicans reserve the right to talk about vetoes, Conrad said, "the head of OMB has a responsibility to talk about how, in a constructive way, are we going to get the appropriations bills completed."
Nussle was nominated last month to succeed outgoing OMB Director Rob Portman, a former GOP House member from Ohio whose style was considered far more approachable by Democrats.
The nomination must go through Conrad's committee, as well as the Homeland Security and Governmental Affairs Committee, before it can be brought before the full Senate for a confirmation vote.
Portman has said he wants to leave his post before Congress begins its August recess.
While other Democrats, particularly on the House side, have been critical of Nussle, he has won support from House Budget Chairman John Spratt, D-S.C., and home-state colleague Sen. Tom Harkin, D-Iowa.
Conrad also blasted a recent Bush radio address where he urged Democrats to finish fiscal 2008 appropriations bills and threatened to veto ones for what he said was excessive spending. "Frankly, that was juvenile. That doesn't help," Conrad said of the address.