That's not a typo. M is saying that he doesn't think vegetables have a lot of flavor. A slightly longer way of saying the same thing is "I don't think vegetables taste like much of anything." You can use that to describe any food that you think is lacking in flavor:
"On its own, tofu doesn't taste like much. It will take on the flavor of whatever you cook it with."
"This soup doesn't taste like much - I think it needs some seasoning."
I think the "like much" part gives the feeling that you think there's not a lot (of flavor) there, or like you're comparing it to other foods and it doesn't taste like anything else. I think perhaps it feels clearer when you look at other instances of "like much." You can commonly hear people say "sound/seem/look like much," where it means that it doesn't sound/seem/look like what you're talking about is a large quantity of something, or that the thing might sound/seem/look unimportant or unappealing, like in:
"Twenty dollars may not sound like much, but it's a lot of money to a child." (it doesn't sound like a large or important amount)
"The house doesn't seem/look like much on the outside, but the inside is beautiful." (from the outside, the house may look small or like it's not a nice place)
"I know he doesn't sound like much to you, but I think he's fantastic." (you think he's not interesting/funny/handsome/appealing, but I think he is)
"This painting doesn't look like much of anything to me, but last week it sold for $1 million." (I thought the painting was uninteresting or unappealing, or I literally thought it was a painting of nothing but lines that don't resemble anything)
I hope this helps!
(not a teacher, just a language lover)
Student or Learner