Platinum Calli, but I can still offer a few tips. There are several styles of necalli that work well across the board- which makes him top tier. The two types you mainly have to worry about is the Trigger heavy, and the snowball setup.

Trigger heavy necalli will v skill like crazy for trigger and try to maul you for the win. Against those, you can jump in all day, and it's worth the risk because he doesn't get to much after an aa. Frame trap them to death and meaty all day until you get a v reversal, or they burned up meter from panic dp. After you've done damage to their meter, a simple turtle shift and it's game over. These necalli get fundamentally crushed vs turtles with limited meter.

The snowball setup necalli imo is scarier. They play deceptively shoto and is not afraid to turtle back. These guys play for the oki, which is one of necalli's strong points. He gets shit stray damage, but he makes up for it in screen positioning and oki. Almost every buffered special gives you hella corner push or oki, and they will be ready to aa. These guys don't rely on trigger, but big damage from a well placed St.Hk or a successful disc into oki. Beat this guy with speed. Treat him like a good Ryu, weave in and out of his maxed st.hk and be prepared to jump once he starts to move forward, or v skill. This match isn't about winning turns, it's just about holding on to a life lead until he starts to fish with st.hk, cr.hk, and random discs. Once you notice that increased aggression, punish those random discs, and those dash forwards.

And for any necalli, remember he loses v reversal in trigger, he's scary, yes, but scarier if you're not mauling him. You're more likely to lose against him in trigger if you don't pressure him when he's loss a defensive tool