Tupou scored two first-half tries for Australia, who trailed before scoring 42 consecutive points in a 56-17 defeat of Japan in Townsville on Saturday.
All three starting front-rowers, as well as replacement hooker Brandon Paenga-Amosa and back-rowers Harry Wilson and Charlie Cale, were Australia's try-scorers in Townsville.
Tupou scored the match-winner in Osaka against Eddie Jones' men a week earlier after coming off the bench and has shown power and skill to indicate he's back near his best approaching next year's home Rugby World Cup.
"He's found a little bit of himself again, and he's been more of himself," Wallabies coach Kiss said, while also noting his combination with good mate and returning lock Lukhan Salakaia-Loto.
"I'm very, very big on making sure the players be themselves as much as possible."
Former Queensland Reds star Tupou agonised over his move from Australian rugby to France, with Racing 92 last season but it's helped him turn back the clock after several underwhelming seasons at the Melbourne Rebels and NSW Waratahs.
"Moving to France, he's found out who he is a little bit more and he's come back and he's really connected with the group here and found that bit of mojo that he likes to thrive on," Kiss said.
With English-based Tom Hooper yet to return to the side, Tupou is the only overseas-based Wallaby currently in the Test rotation.
The coach has remained in touch with Racing 92's staff to ensure they have his services for the two-Test tour of Argentina that begins later this month and hopefully beyond.
"All good, as I believe, at this stage.
"I'll be talking to the coach and the team manager of Racing, this week, again, to make sure they understand how we're looking after Nella and making sure we're doing the right thing with him and working him hard.
"So they can trust the process as well. But, yeah, he'll be with us."
Jones joked post-game that Tupou played as if there was a pizza on offer for every try and reckoned he would even deliver one to the change-rooms himself.
"No pizza, I'll have to hit him up about that one," Tupou grinned.
"I've got a lot of love and respect for Eddie, actually. Nothing against that, he loves me, I know that."
Tupou said he wanted to "take it to the next level" after finding his feet in France.
And he said Kiss's tweaks were helping him get there.
"To get the ball in my hands as a forward, less running without the ball, more running with it," Tupou said.
"We're still working on it, but it's good to see forwards scoring tries."
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