Heh. Ok then. A quick overview of them.
Combat in Tales of Berseria resembles brawlers. There’s a big emphasis on combos and special attacks, but you can configure combos freely to fit your preferred game style. You have a party but you only control one character at a given time. It’s a bit button-mashy, very flashy, and it can be really enjoyable for fans of brawlers.
Combat in Ni No Kuni, on the other hand, resembles a bit the ATB system in Final Fantasy games. You have a party, but the characters in the party don’t fight directly. Each character has a team of familiars, small spirits that can be used - one at a time - in battle. Each familiar has a set of attacks and skills that you may choose in quasi-turn-based fashion, and then you have a cooldown, and then you choose another action. You can change familiars in battle, and your character can also cast spells.
What both have in common is how they rely on using the weaknesses of your enemies for your advantage - elemental weaknesses mostly, but also a variety of useful conditions and statuses you can inflict on them. They’re also both real-time. Other than that, they are very different in feel.
How’s that? A bit better?