“Heaps Good” Means “Very Good”

In informal Australian English, heaps good usually means “very good”, not “a pile of good things”. Here heaps works as an adverb, much like very or really. The ABC quotes an Australian National Dictionary Centre researcher who says the expression is used across Australia, although it is often perceived as particularly South Australian.

A: How was the gig?
B: Heaps good.

The tone is very casual and suits conversation with friends; very good or excellent is safer in formal settings. Note the different structure in heaps of time, where heaps of comes before a noun and means “a lot of”. In heaps good, heaps directly intensifies the adjective. With people unfamiliar with Australian English, really good will be clearer.

https://www.abc.net.au/news/2018-10-19/where-does-the-term-heaps-good-come-from/10071780
https://dictionary.cambridge.org/dictionary/english-chinese-simplified/heaps