Why does a 99 Nissan Altima make noise when steering?

First thing to do is check your Power Steering fluid level. If it is full, and that does not fix your problems, check all of your power steering lines and make sure there are no kinked/pinched lines. If none of this fixes it then you should have it looked at by your local mechanic. If none of the above strategies fix it, then there is a slight chance that your Pwr Steering pump is bad.