I've found the gdp deflator for a country over a 25 year span. If I have nominal consumption for the same time series, then I just have to divide nominal consumption by the p-level I found with the deflator right?
GDP deflator deflates GDP. If you want to deflate consumption, you'd most likely want to use the consumer price index (CPI) to deflate. GDP deflator would take into account, for example, the price level faced by producers (PPI).