Nida's human form has single target spears, Jayce clears entire waves and has aoe poke with his Q + E.
Jayce wins this one.
Nida has a single target heal combined with an attack speed steroid.
Jayce has a group MS boost and a seperate AS boost.
This one is slightly in Nida's favor generally, but is pretty situational
Nida has traps that don't act as wards at all. Even Teemo's shrooms provide more vision.
Jayce's human form also has huge burst, aoe damage, a gap closer, AND CC.
Jayce wins this one.
Overall, Jayce is stronger at both sieging AND all ins, but he has to pay mana to do so, and can't do it indefinetly.