No, Nagato is stronger
Itachi would have died from Planetary Devastation if not for Bee and Naruto.
-Totuga blade wouldn't seal a jutsu, from all we've seen it will only seal souls once it has impaled something. When it was cutting up Oro's serpent heads it didn't seal them nor any of the rocks it hit. The only times it did seal something was an opponent's soul after being impaled.
-Susanoo doesn't move, Itachi would have been sucked up into the attack
-I doubt Yasaka Magatama is as strong as a Tail Beast Bomb, even that couldn't even destroy PD during the Pain fight. If YM was as strong as a TBB, he wouldn't have enough chakra to do multiple.
-Itachi wouldn't have enough time or chakra to attempt multiple, even so, there is no guarantee PD would be destroyed, unless you make very generous assumptions.
-Even if Susanoo went up with him, the debris could crush him from under Susanoo, and even if it didn't, a shield won't protect you from being crushed by a gravitational weight.
-Even if Itachi survives PD, he'll not only be exhausted physically, he will also have to survive the fall while at the same time not be crushed by any huge falling debris. Keep in mind Nagato will still be there ready to fight.