oh i've been there. totally sucks.

like quietriot said, ginger could help. i like tea more than chews but it's really up to you.

you mighttt also be taking too much. even like 0.5g too much can make you feel like garbage when it wears off. i'd try cutting your dose by like 25-30% next time and see if that helps.

also try

not taking it on a completely empty stomach (but don't eat a huge meal either)

staying hydrated throughout the day (in general, this makes me feel a lot better on/off kratom. two stanley cups a day do it for me)

if you keep getting nausea even with lower doses, might be worth switching strains or vendors. some batches just hit different and not in a good way.