Percents Nair will put the opponent in a tumble animation.

[Lochy]

As you may know Ness has a jablock with Nair. Usually at around 40 percent Ness can nair and then (if the tech is missed) lock them with his jab. This leads into a plethora of options like:
F smash
Pk Fire -> Grab
Grab
Falling Up Air
Pk Fire -> F smash

Without further ado these are the first percent for each character that will allow you to lock them.

Note: Mii Fighters were tested with default weight setting.

Bayonetta: 32%
Bowser: 42%
Bowser Jr.: 36%
Captain Falcon: 37%
Charizard: 39%
Cloud: 36%
Corrin: 35%
King Dedede: 40%
/ Pit Bros: 35%
Diddy Kong: 34%
Donkey Kong: 41%
Dr Mario: 35%
Duck Hunt: 34%
Falco: 31%
Fox: 31%
Ganondorf: 39%
Greninja: 34%
Ike: 37%
Jigglypuff: 28%
Kirby: 31%
Little Mac: 31%
Link: 37%
Lucario: 35%
Lucas: 34%
/ Marth and Lucina: 33%
Luigi: 35%
Mario: 35%
Megaman: 36%
Meta Knight: 31%
Mewtwo: 29%
Mii Brawler: 36%
Mii Gunner: 35%
Mii Swordfighter: 35%
Mr. Game and Watch: 30%
Ness: 34%
Olimar: 31%
Pacman: 34%
Palutena: 34%
Peach: 33%
Pikachu: 31%
R.O.B: 37%
Robin: 34%
Rosalina: 31%
Roy: 34%
Ryu: 36%
Samus: 37%
Sheik: 32%
Shulk: 36%
Sonic: 34%
Toon Link: 34%
Villager: 35%
Wario: 37%
Wii Fit Trainer: 35%
Yoshi: 37%
Zelda: 32%
Zero Suit Samus: 31%

Hope this helps you guys!

 

[Funen1]

This was already covered in this topic a while ago, but hey, couldn't hurt to refresh people about this I guess.

 

[Lochy]

This was already covered in this topic a while ago, but hey, couldn't hurt to refresh people about this I guess.

Even though it was covered, my list is more up to date because it was tested with every character and some weight values were changed for certain characters.

 

[Funen1]

That is true, though iirc the percents didn't change for every character that had their weight adjusted, and any new values could've also been posted in the original thread (I doubt anyone would mind the bump anyway).

 

[Uffe]

I forgot about weight gains and weight loss on some of the characters. I haven't gotten around to testing the DLC characters, and I've yet to still get Bayonetta. But hey, good job.

 

[marioarturo2000]

The list contains the first percentage, but is there a last percentage or the characters always tumble after crossing this minimum?

 

[EnhaloTricks]

The list contains the first percentage, but is there a last percentage or the characters always tumble after crossing this minimum?

Always after. The minimum percent is good to know cause it leads to a tech chase or a potential jab lock to death by bat.