December tax collections were more than $40 million above target.
Overall revenues were boosted by a surge in individual income tax collections, which came in more than $70 million ahead.
Legislators already differ on whether the bill amounts to an expansion of gambling.
A bill headed to the House would divert some of the revenue earmarked for local entities, and send it back to the casinos.
January revenues were higher than predicted, but sales tax revenues are falling short of predictions for this fiscal year.
With the state announcing a budget surplus of more than $2 billion, some have called for the state to return funds back to local governments.
Indiana's revenue growth is on pace for the state’s surplus to exceed $2 billion by next summer.
Indiana's economy appears to be improving, based on the latest jobs report, and that could foreshadow higher state revenues for next year.
Indiana collected $24 million more in taxes than it forecasted.
The Indiana State Fair brought in about $100,000 less than expected, which officials attribute to low concert attendance and a hot summer.