No, nimitta in the sense of “radiant light seen as the precursor to jhana” does not occur in the suttas. What we call nimitta is, in the suttas, called rūpa or obhāsa.
Generally speaking, in meditation contexts, nimitta means “an aspect of experience that, when attended to, promotes the growth of similar or related qualities”. To give rise to energy, for example, you pay attention to the paggahanimitta, i.e. you do the kinds of energetic things that help rouse further energy. To make the mind peaceful you attend to the samathanimitta, i.e. to peaceful and calming things like the breath. It is in this sense that satipatthana is the samādhinimitta ("the foundation for samādhi), i.e. the practice of satipatthana meditation leads to jhana.
Previous discussions:
I’m afraid Ajahn Brahm is mistaken. In this passage, nimitta means “basis, cause, reason”. The passage is about understanding the reasons why the “light” (i.e. obhāsa, i.e. what the Visuddhimagga calls nimitta) arises or passes away. Surely this is one of the passages that influenced the later usage, but it is still a distinct sense.
Here the word nimitta is the first jhana itself, not the “nimitta” for the first jhana. The phrase taṁ nimittaṁ must refer back to something in the previous statement, which refers solely to the first jhana, not to any “light nimitta”.
In this case, the point is that the first jhana is the basis or foundation for further development of samadhi. So it must be stabilized and grounded before the second jhana can be realized.
For those of historical bent, I first wrote about this more than twenty years ago, in A Swift Pair of Messengers. Time flies!
Nimitta in the suttas probably never means ‘radiant reflex image in meditation’. This was referred to rather as ‘light and vision of forms’, the ‘radiant mind’, etc. The commentarial usage of nimitta for this light is possibly influenced by such passages as this.
‘When, good sirs, the nimittas are seen, illumination is born, and light manifests, then Brahma will manifest.’
At AN 5.193 the various pollutants and disturbances to water, compared with the five hindrances, prevent one from seeing ‘the nimitta (reflection) of one’s own face’. The commentarial term ‘apprehending sign’ (uggaha nimitta) was possible derived from passages such as AN 6.68 and SN 47.8; but here the meaning seems to be ‘apprehending the character of the mind’, how the mind responds to various ‘foods’. AN 6.68 shows that ‘apprehending the nimitta of the mind’ is a preliminary stage of meditation, before fulfilling right view and then right samādhi. In at least some meditation contexts nimitta just means ‘cause’. It refers to some quality, aspect, or feature of experience which, when paid attention to, promotes the growth of a similar or related quality. This meaning fits in well with the contexts in this work, so I have adopted the rendering ‘basis’ rather than ‘sign’, which does not carry a causal implication. AN 3.19 says that a monk who does not ‘carefully resolve’ on their samādhi nimitta (here = meditation subject, perhaps satipaṭṭhāna) in the morning, midday, or evening cannot grow in good qualities. At MN 128.28 the phrase ‘I pay attention to the light-nimitta’ occurs, but even here I would regard the term ‘attention’ as hinting at a causal implication, consistent with the usage in the sutta.