Not nondualism (which would be avdvayatā), but kasiṇa meditation is said to be “non-dual” (advayaṁ). Eg AN 10.25:
Pathavīkasiṇameko sañjānāti uddhaṁ adho tiriyaṁ advayaṁ appamāṇaṁ
Someone perceives the meditation on universal earth above, below, across, non-dual and limitless.
Here, as always in the suttas, the word kasiṇa has nothing to do with the commentarial idea of a “physical disk”, but means “universal, totality”. In this kind of case to leave kasiṇa in the original language is a mistake, as it creates needless misunderstanding.
From context, it is clear that this is a term for a state of consciousness, and all the terms are more-or-less synonyms. Note the similarity between this phrase and the stock description of the brahmaviharas. These are all different ways of describing jhanas achieved in different ways.
So certainly in this case, and probably when talking about jhanas generally, it seems the term “non-dual” can be used; of course it is more common to simply describe such states as “oneness”.
Whether this is the same as what modern theorists talk about when they talk about “non-dualism” is of course a separate matter. But generally speaking, the "non-dual"schools hark from the Upnishads, and I believe the states of samadhi such sages were realizing were the jhanas. So if it is not identical it certainly shares roots in a similar kind of experience.