Kyrgios was penalised for a slow rate of serve during his defeat to Karen Khachanov at the Cincinnati Masters earlier this week.
The decision by umpire Fergus Murphy sparked chaotic scenes for the remainder of the match.
Kyrgios smashed two rackets in a corridor after leaving the court without permission and launched a number of verbal tirades at the official.
After being told he was serving too slow, Kyrgios fumed: “You’re telling me Rafa plays that quick every service ball? That’s hilarious bro, hilarious.
“I missed the ball, the guy starts the clock.
“If Rafa plays that quick I’m retiring. Retiring from tennis. Absolute rubbish… disgrace.
“Get me some footage of Rafa playing that quick, that game. If you can find any of that I’ll shut my mouth and never speak again.
“I guarantee you’ll find none of that, none of it.”
Kyrgios uploaded a video of himself serving side-by-side with a Nadal serve and the Spaniard takes considerably longer, validating Kyrgios’ point.
The 24-year-old then took to Twitter to fire a shot at the 18-time Grand Slam winner.
“I mean it’s not even a question,” Kyrgios wrote. “I still played within the 25 seconds when the shot clock started. Haha could only imagine if I was as slow as 41 seconds.”
The ATP are still investigating to see if Kyrgios committed a “major offence”.
If found guilty the world No 27 could face a suspension from the tour.
And former British No 1 Greg Rusedski wants Kyrgios to seek help.
“Last time he got pushed out of the game and had to take time away from it,” Rusedski said on Amazon Prime.
“You look [now] and did that really work? He hired a sports psychologist, did it make a difference in his behaviour?
“I think he needs a regular therapist to deal with other issues so he can behave himself on the court.”