Murray was in the warm-up area at Wimbledon alongside doubles partner Pierre-Hugues Herbert while Kyrgios and Nadal were battling on Centre Court.
During the early exchanges, Kyrgios attempted to wind up his opponent by complaining to the umpire and using underarm serves.
World No 2 Nadal dug deep to earn a 6-3, 3-6, 7-6(5), 7-6(3) victory to progress to the third round.
Midway through their match, Murray and Herbert took to Court 1 and won their opening match of the tournament.
The Brit was asked if watching such a blockbuster on Centre Court increased his desire to return to singles.
“We were watching it together in the warmup area before we went out to play,” Murray revealed.
“It was some interesting stuff going on out there (smiling).
“Yeah, I mean, I have thought about playing singles again.
“Yeah, it’s something more recently since I’ve been back on the court, there’s been more discussions with my team.
“I’ve been asked about it by some of the guys in here.
“Hopefully it’s not too far in the future. But it’s not something that this week I’ve given much thought to.
“I’ve been kind of concentrating on the doubles, enjoying that for now.”
Meanwhile, Murray is in mixed doubles action alongside Serena Williams this evening (not before 5.30pm).
It is highly likely their match will get underway on Centre Court, so long as the three scheduled matches finish before those on Court 1.
Murray and Williams confirmed they were teaming up for the first time on Tuesday evening after the American came through her singles match unscathed.