Template literals with nested backticks(`) in ES6

From ES6 In Depth: Template strings by Jason Orendorff:

If you need to write a backtick inside a template string, you must escape it with a backslash: `\`` is the same as "`".

Your query should be:

var query = `UPDATE packet
  SET
  \`association\` = "3485435",
  \`tagname\` = "Simos"`