[Bomb Dropping Maiden] Chi-Chi is an interesting unit; her ability to debuff the attacked enemy is nice on a Super PHY team, especially for Super Battle Road; the fact that she can be self-sufficient is pretty cool and the unit also has the ability to stun, but her stats are very low and the B Rank Potential System certainly doesn't help.
Debuff Stunner (Passive) Self-sufficient
B Rank Potential System Lacks common links
How to Get
[ JP version only]
Causes supreme damage to enemy with a rare chance to stun
12 Ki Multiplier
Type Ki +2 and ATK & DEF +50%
Attacked enemy's ATK & DEF -20% for 2 turns; when HP is 50% or above, Ki +3 and ATK & DEF +60%
Chi-Chi has a supreme damage multiplier and a 130% 12 Ki multiplier, nothing special considering the fact that she has a very bad Potential System, which is already enough to limit her performance offensively and defensively, and only a 60% ATK boost from her Passive.
2 Ki and a 50% boost to ATK and DEF sounds kind of redundant and weird since the [Martial Artists Fight] Goku that just received a Dokkan Awakening has pretty much the same Leader Skill but gives 10% more to both stats; Chi-Chi is not really meant to be a Leader.
Chi-Chi's Passive makes her self-sufficient, giving her 3 Ki and a 60% boost to both ATK and DEF as long as your HP are above 50%, which is cool, but the boost is too low
Bulma (Youth) shares both of Chi-Chi’s Ki links, “Battlefield Diva” and “The Incredible Adventure”, which is more than enough, together with her Passive, for an automatic Super Attack; in addition to this these two units activate for each other “Guidance of the Dragon Balls”, their strongest ATK link.
The support unit given out as a gift for the new year links pretty well with Chi-Chi, she can activate “The Innocents” for her and she adds 3 Ki between her Passive and “Battlefield Diva” and a 20% ATK and DEF boost.
Chi-Chi is not a unit you would want to put orbs into, the best thing you can do is to give her the lv.5 Additional she gets and not touch anything else; she will have a 10% chance to reduce the enemy's ATK by an additional 20% and get a second chance at stunning him.
Should I use Elder Kais/Grand Kais?
Chi-Chi does not have a farmable Super Attack, your best bet to max her out is to utilize another copy of her or a summonable one since she is actually the best unit with that name so far.