QGIS is the gold standard for free GIS software. While it is not a one-click converter, it is the to get from PDF to TNS.
You need a specific tool to put those images into a calculator format. The most popular free tool for this is Nspire.img .
that can convert PDF pages into readable images formatted specifically for TI-Nspire handhelds. GitHub TNSFileConverter
Used by TunerStudio MS (automotive ECU tuning software). These are proprietary log or project files. No free converter exists from PDF.