Trump made the remark at a G7 meeting, which includes 5 other NATO members. He has repeatedly attacked and cast doubt on the organization’s future. NATO is a mutual defense treaty created to defend against the Soviet Union, which includes 29 members across North America and Europe. NAFTA is a free trade agreement instituted in the 90s between the United States, Canada, and Mexico. The two have no connection.

The Hill – Trump told G-7 leaders that ‘NATO is as bad as NAFTA’: report
Axios – Scoop: Trump’s private NATO trashing rattles allies
The Washington Post – Trump misunderstands NATO so badly, he thinks Brazil could be part of it