Tatsumi Kimishima told Thursday's Kyoto Shimbun newspaper that the momentum for Switch is stronger in some markets than that of the Wii, a smash-hit household console that sold more than 100 million units worldwide.
Kimishima said he expected Switch to sell "more than 20 million" units in the year to March 2019.
Nintendo launched the console in March 2017 with a price tag of $300 (roughly Rs. 19,243) and aims to sell 14 million units through March 2018.
Switch can be played both as a household console as well as a hand-held device.
It has flown off the shelves and also sold well online, sparking an upgrade in the Kyoto-based company's annual profit forecast.
"We are seeing momentum beyond our expectations," Kimishima told the Kyoto Shimbun.
"People have accepted the unique game experience that you cannot find anywhere else, where you can take it outside while also using it as a household console," he said.
"In some countries, the pace is beyond what we saw with Wii," he said.
In a separate interview with the Asahi Shimbun, Kimishima said holiday sales had been in line with expectations.
He also said the company was "starting to think" what console would come after the Switch.