Hello @Gourav Ruj
Thanks for reaching out to us. I just checked with the pm of Bot Framework Composer, there is no native support for calling Amazon Lex to the composer now. Sorry about this.
As a workaround, there is an extensibility model that the customer can use, and they can build their own libraries for "recognition" which they could use to write their own integration.
I will highly recommend you to check below resource to see if that's the way you want to integrate Amazon Lex to Composer:
What is Composer Extention: https://learn.microsoft.com/en-us/composer/concept-extension
How to extend Composer with extentions: https://learn.microsoft.com/en-us/composer/how-to-use-extensions#add-a-custom-publishing-extension-and-user-experience-from-composer
Sorry about the product limitation and thanks for your understanding, I hope the above information helps.
-Please kindly accept the answer if you feel helpful to help the community, thanks a lot.