You have already received several answers. Rather than repeat them, let me give you the resources so that you can answer this and similar questions on your own. Look for a book titled 『大阪ことば辞典』 by 牧村史陽 (Makimura Shiyō) and published by Kōdansha, 1984. The ISBN is 4-06-158658-0. Below are a few short excerpts.
- (page 376) セヤ: そうやの訛。そうだ。例:セヤセヤ(そうだそうだ)。セヤよって(そうだから)。
- (page 543) ネン(助): の。のだ。(ネ・ネヤの項参照)例:そやネン(そうなのだ)。行ったるネン(行ってやるんだ)。行ったんやネン(行ったのだ)。何しててやんネン(何をしていらっしゃるの。これが下品になると、何してけっかるネン)。
- (page 508) ナァ(助): ね。原語はそやノォ・ええノォののう(喃)である。例:あのナァ。そやナァ。ええナァ。知らんナァ。西鶴の『好色一代男』(天和)巻六に「うまいなあと云はせしことも」
This reference also indicates the accent for all terms. I am not able to replicate the notation here, though.
そやな
andせやな
in meaning, but there's an image ofせやな
tending to be used more by people over 40 andそやな
used by comparatively younger people according to this article.