About half these types on acsearch say Poseidon. The other half say Tyche of Arados which is most certainly the correct attribution.
This is very helpful @ancientone I was totally wrong. Thank you so much for your help, it is greatly appreciated. Regarding the 3-Standard motive, it was used by Caracalla, Geta, Elagabalus, Julia Mamaea, Severus Alexander and Gordian III. It is remarkable that the Roman provincial coins from Nicaea mix Latin and Greek letters and forms (e.g. V instead of Y, OY or B in AVR and SEV, AVG instead of SEB etc.) From the one's I posted, the first one, Severus Alexander, is probably the most common Roman Provincial coin and there are many variants [buste lauré ou radié, à dr.", "NIKAIEΩN (sur une ou deux lignes)"], and all of them are SGICV 3287 and Rec Gen II p. 477, 617; most collectors consider this type totally uninteresting, or even boring, although there are some collectors that like to collect the variants. The second one is from Elagabalus because on his coins the letters are between the standards and not below as on the reverse of Severus Alexander. Receuil General 571; BMC Pontus p. 167, 93