Complex sentence: Pettibone was planning on speaking about her support of white nationalism at a conference entitled "Globalism vs the Ethnostate" according to "Searchlight", which called her a leading figure in "The Growing Nazi Axis" in the United States.
Split into simpler sentences: Pettibone was planning on speaking about her support of white nationalism at a conference entitled "Globalism vs the Ethnostate" according to Searchlight. Searchlight has described her as a leading figure in "The Growing Nazi Axis" in the United States.