Finger on nose is almost a universal gesture. Whenever 'finger on nose is mentioned while describing gestures, in most of the cases, it is the index finger which is kept in mind. That gesture could have variegated semiotics in each of the cultures where it is used. What the thread initiator said he was looking for was the specific cultural connotation in the context that he cited, Viśvanātha Cakravartin's commentary (ca. late 17th century) on the Bhāgavata Purāṇa 10.9.7 (uttārya gopī...).
There are two bases of context here, the verses before and after 10.9.7.
BhP_10.09.006/1 sañjāta-kopaḥ sphuritāruṇādharaṃ sandaśya dadbhir dadhi-mantha-bhājanam
BhP_10.09.006/3 bhittvā mṛṣāśrur dṛṣad-aśmanā raho jaghāsa haiyaṅgavam antaraṃ gataḥ
BhP_10.09.007/1 uttārya gopī suśṛtaṃ payaḥ punaḥ praviśya saṃdṛśya ca dadhy-amatrakam
BhP_10.09.007/3 bhagnaṃ vilokya sva-sutasya karma taj jahāsa taṃ cāpi na tatra paśyatī
Second, the cultural background of the user of the expression Viśvanātha Cakravartin and his period:ca. late 17th century.
Why I say period is the following:
Among the Telugu speakers, apart from the universal meaning of "silence!" there is the meaning of intense surprise/amazement found in expressions such as mukkuna vēlēsukunnāru = they put (past) the finger on the nose, meaning they were all amazed at what happened or at what they saw/heard.
But I observed another finger on nose gesture in my previous generation, in which the index finger moved from the tip of the nose vertically straight upwards upto the forehead while waving the head horizontally, showing the tongue out usually folded with its tip upwards or downwards, to communicate the meaning (usually expressed in words immediately after removing the tongue part of the gesture), " Oh! nno! is it not so wrong, so inappropriate?"
This expression is no longer found used. It seems to get considered as oldish.
So time ca. late 17th century and the region and cultural group of Viśvanātha Cakravartin .