Iwobi appeared for England in the youth ranks but opted to play with the African nation in 2015.
The Lagos-born 21-year-old has scored four goals in 14 appearances for Nigeria since joining the side at Under-23 level.
"I was growing up in England and England was the only national team I knew, so I was actually very pleased to play at national level," Iwobi told Soccer Laduma.
"However, my family are all from Nigeria, I was born in Nigeria, my uncle (Jay-Jay Okocha) is a legend in Nigeria.
"That's why I thought I would give it a chance. That's why I went to the Under-23s and somehow felt more welcome, and I thought it's where I belong, so I made the decision to switch."
Iwobi netted twice in Tuesday's 4-2 international friendly win over Argentina.