According to http://docs.aws.amazon.com/lex/latest/dg/API_Operations_Amazon_Lex_Model_Building_Service.html you can create or update bots and intents/slots (Put{Bot|Intend|Slot}, Create{Bot|Intend|Slot}Version).
So by using Put* I can configure a bot and with Create*Version I can publish one, but in order to publish it, first you need to build it and I can't find an API method for that.