No. Chasing is defined by inherently transphobic sexual objectification and tokenization of trans women, not by dating trans women repeatedly. Some trans women out there will have an attitude towards the subject that mostly reflects their self hatred and their inability to see themselves as desirable, with a very strong undercurrent that only cis or perfectly cis passing women could be of any sexual value to straight men. To them, it will be inherently suspicious if somebody even knows they are trans before they start dating and is still interested in them. The idea that "has dated more than one trans woman" is a valid definition of chaser comes mostly out of that mindset, and i must stress that this mindset in itself is both violently and brutally transphobic and doesn't even begin to capture the wide range of problematic and sometimes downright threatening behaviors exhibited by chasers.