The singer's wife Lauren Kitt is expecting the couple's second child.
The couple announced the baby news on Friday, May 24 with a sweet post on Instagram.
Underneath a photo of Nick cradling his wife's baby bump as their three-year-old son Odin looked on, they wrote: "Thank You God for giving us the greatest gift we could ever ask for."
The news comes almost a year after Nick revealed his wife had suffered a miscarriage. Lauren also lost a child before she gave birth to Odin.
They wed in April, 2014.