I've done some testing and if the opponent doesn't tech, at mid range percentages you can set up a mini chain grab by using Fthrow and hitting the opponent with the first hit of your Nair when they hit the ground.
Not sure if this is an actual chain grab but it might be useful if it works.
While this is true it requires the opponent to be an specific weight and % combination and for them not to tech. At low %s it works on most fast fallers or floaties who don't try to jump, but again they need to not tech also. The biggest problem with this is that floaties (and fast fallers once they reach a certain %) can just jump away and you're going to be too far away to chase accordingly (unless they are very slow in the air).
Edit: Also someone already posted this but, if you F-Throw and they don't tech it is much better to do a B-Air since it will jab lock your opponent. You can then do 2 weak attacks (Jab makes them stand up, don't use it. I think you might get away with 2 first hit N-Airs, but maybe you can only do 1 due to landing lag) into a regrab or a smash or anything you want.
D-Throw IMO is much better for "chain" grabs. Jab and U-Tilt set the opponent up perfectly for a regrab and on a good number of chars it's guaranteed at 0-10%. For those chars that it isn't guaranteed I like to U-Tilt 2ce, if they dodge the second U-Tilt then I regrab, if they don't then I SH and wait for an AD. If they AD it's a regrab, if they don't then it's an U-Air (so close to the ground that they can't dodge it anymore).
Basically grabbing someone at 0-10% almost always leads into me getting a 30-50% string or the opponent utilizing his double jump which also puts me in a very favorable position.