Complex sentence: It has been said that this impact will not only change Chalchihuites security but also its economy, since people fear that not so many tourists will go there due to the insecurity its causing to not only Chalchihuites, but to Mexico.
Split into simpler sentences: It has been said that this impact, will not only change Chalchihuites security but also it's economy. Since people fear that not so many tourists will go there due to the insecurity its causing to not only Chalchihuites, but to Mexico.