I'm not saying they make loads of chances mate. I"m underlining your point by stating that the way he has them set up requires a forward to snap up whatever comes their way.
Karanka has taken the not unwise decision to make sure he's not leaking goals and remaining competitive in most games and calculating that he can turn enough close encounters into three points to add to the draws they get.
I actually find that very cool and calculated for a promoted team, because too many of them have come up previously and thought it was wise to go toe to toe with teams with lots of experience and a lot more attacking talent. It's a very mature strategy to establish Boro in the PL.