Can we say Satchidanand (or Satcitananda) refers to joy of being established in inner awareness which is our unchanging, eternal and divine existential truth/reality?

As per wiki page of Satcitananda (I would use spelling of Satchidanand), https://en.wikipedia.org/wiki/Satcitananda , Satcitananda (सच्चिदानंद) is a "description for the subjective experience of the ultimate unchanging reality", called Brahman in Vedanta. Satcitananda represents "existence, consciousness, and bliss" or "truth, consciousness, bliss".

I think 'existential truth' or 'existential reality' is a good meaning for sat.

I think the Sanskrit word 'anand', which is also used in Hindi, can be translated as joy. 

While chit is typically translated as consciousness, I think chit can also be translated as (inner) awareness.

So I think we could say that Satchidanand is "existential truth, (inner) awareness, joy" or "existential reality, (inner) awareness, joy". To express it slightly loosely but in a way that may be easier for folks to understand, we could say that Satchidanand refers to (the experience of) joy of (being established in our inner) awareness which is our existential truth (or reality) (and which is unchanging, eternal and divine).