I use MS Bot Framework for creating bot for MS Teams.
I need to figure out how to implement a lookup field so that it fetches information through an odata feed from a sharepoint list
I can give little help on the SharePoint side. If possible, you might consider using a filter to limit the amount of values returned:
http://www.andrewconnell.com/blog/Applying-Filters-to-Lookup-Fields-with-the-SP2013-REST-API
SharePoint 2013 REST How to select a look up field and also filter based on look up field?
Depending on the size that a filtered set returns (if you do so), you might also/instead want to use paging:
https://platinumdogs.me/2013/05/14/client-and-server-driven-paging-with-the-sharepoint-rest-api/
https://sharepoint.stackexchange.com/questions/45719/paging-using-rest-odata-with-sp-2013
On the botframework side; how do you want to present to the users? Do you want to supply a limited amount of data (say 20 values, for example), then have them give feedback on whether or not that contains the data they need? If so, you can split the data returned from SharePoint into chunks and use a waterfall dialog to accomplish that. Optionally, if you paged data from SharePoint you could; get one page, query user, get another page, query user again, etc. until whatever goal was achieved.
Unfortunately, you're not giving enough information on the actual goal or what you are expecting this functionality to look like in the end.