Make sure to eat something when you start to feel this way. I know that's pretty basic, but it always worked for me when I would start feeling nauseous from hydrocodone.
What dose do you usually take, including the acetaminophen dose?
Great ideas in this thread, especially CWE and laying down.
I've found the best way to dose opiates is to take them on a completely empty stomach (4 hours after eating), then to eat 20-30 minutes after dosing. That way, by the time you're finished eating, the effects will really kick in, and having something in your stomach will really help with the nausea.
If you smoke weed, a hit or two about an hour after dosing is a fantastic anti-emetic and a great booster (brings on the nod).
ginger, benedryl, and laying on your back all help.