Is burping a side effect of chemo?

Hi,

My husband was recently diagnosed with stage 4 adenocarcinoma lung cancer metastasized to the brain. They removed one of the masses from his brain, did targeted radiation on the brain and on Monday he had his initial chemotherapy session. We noticed he is burping a lot since the chemo. Is this a common side effect? Tonight he said he feels "a bit like I'm about to vomit" so he just took the anti-nausea medication he was given "as needed" and we hope it helps. Is the burping also a side effect of the chemo? If so, what can we do for that? Any advice is appreciated.