<<< native
[ ESubsup
    (EIdentifier "X")
    (ESubsup (EIdentifier "Z") (ENumber "4") (ENumber "3"))
    (ESubsup (EIdentifier "Y") (ENumber "2") (ENumber "1"))
, ESymbol Rel "="
, ESubsup
    (EIdentifier "X")
    (ESubsup (EIdentifier "Z") (ENumber "4") (ENumber "3"))
    (ESubsup (EIdentifier "Y") (ENumber "2") (ENumber "1"))
]
>>> tex
X_{Z_{4}^{3}}^{Y_{2}^{1}} = X_{Z_{4}^{3}}^{Y_{2}^{1}}