CNN has this interesting interview with Ron Paul, on the national Republican convention rule that says only a candidate who has a majority of the delegates in 8 states or territories may be placed in nomination by a nominator speaking from the stage. It is widely believed, without contradiction, that the rule was passed in 2012 to prevent anyone from giving a speech from the podium to nominate Paul.
I guess this rule eliminates Kasich from being nominated.
The rule can always be changed. Also delegates are free to vote for someone who wasn’t formally nominated with a speech at the podium.