Not sure if it's on video. Here's extracts from NY Daily & Y! Sports.
Leading up to his 2015 match against Brazilian fighter Jose Aldo, McGregor repeatedly resorted to disgustingly bigoted attacks. In a reference to colonialism, McGregor said, "If this was a different time, I would invade his favela on horseback and kill anyone that was not fit to work." McGregor later said, "What I really want to do is turn his favela into a Reebok sweatshop."
“What I really want to do is turn his favela into a Reebok sweatshop,” McGregor said
This aren't even debatable in terms of being racist, and you know it.
Some others that may or may not be taken out of context: http://people.com/sports/conor-mcgregor-floyd-mayweather-racist-dance-boy/
Kinda depends on whether you give him the benefit of the doubt for not knowing negative connotations (historically) behind the word.