Waghorn joined the Gers from English League One outfit Wigan Athletic in the summer transfer window.
The 25-year-old striker has proved to be a brilliant acquisition for Rangers and has scored as many as 17 goals so far this season.
Two of those goals came against Alloa Athletic at Ibrox in Glasgow on Saturday afternoon, as the Gers returned to winning ways in the Scottish Championship with a comfortable 4-0 triumph.
Winger McKay has been impressed with the performances of the former Sunderland and Leicester City striker so far this campaign.
“Waggy’s done great since he came in,” the 20-year-old told The Daily Record. “He’s got himself on the scoresheet plenty and he’s a natural finisher. It’s such a bonus for us to have him here.
“As a winger, you love having a guy like him to aim at. I’ve probably set up a few of his goals, which is pleasing.”
“If you give it to Waggy, nine times out of ten he’ll hit the net,” added McKay. “He can definitely get a lot more goals because there’s a lot of the season still to go. I’m sure he’s plenty to come yet.”
Rangers are at the top of the Scottish Championship table at the moment with 36 points from 13 matches, five points clear of second-place Hibernian.
Mark Warburton’s side will take on Livingston away from home in the league after the two-week international break.