First of all I'm not claiming that Obama intentionally surveilled Trump or his top associates. There was a properly authorized FBI investigation of his campaign. Comey said that involved no surveillance of Trump or his building. Where did Nunes say this happened?
Also, none of the evidence I cite to comes from leaked sources. Clapper and Rogers testified to the Russian hack and release. Comey and Rogers testified to the FBI investigation. The info on Manafort and Flynns nefarious money deals came from Flynn's filing and the AP investigation of Manafort.
Name the alleged leaks YOU are referring to that were obtained by Obama or his administration's alleged surveillance of Trump or his top associates. If you are including the FBI investigation in that so indicate.