I'm trying to find a word or phrase for a particular type of reaction similar to a laugh. The reaction is hard for me to describe, but an example of it can be found in this video. The reaction is actually before the list begins, around the 0:08 second mark.
The reaction I'm after is sharper and quicker than the one in the video: a short, semi-sharp breath out through the nose, usually accompanied by a very slight nod of the head. It's not a true laugh, but does show amusement/appreciation.
"They're not that bad. Once you get over their endless search for assassination plots, they're a good group to hang out with."
Dave grinned. "You have my condolences," he said, ____-ing.
(meant to show light sarcasm)
Most of the synonyms for laughter suggest loud or prolonged sounds, neither of which fits the reaction I want. One word which comes close is snort, but that suggests something a lot louder and less controlled than I want. The closest I have come to a description is:
He suppressed a laugh.
Still not quite what I want, since the character isn't really suppressing anything.
What is a good word/phrase for this reaction? I'm after a word to describe the reaction to something which is only mildly funny or perhaps sarcastic, and does not induce full laughter.