nginx isn't parsing php in nextcloud install - php

Question

I'm trying to set up a nextcloud server on a raspberry pi 3 (raspian stretch).
I've been generally successful in getting the stack built using nginx and mysql. However, I've encountered a problem with nginx not parsing php.
That is, when I navigate to the pi's nextcloud install, the browser prompts me to open / save index.php (the next cloud login screen), which tells me the server isn't parsing it at all. I found one link to the nextcloud documentation which suggested adding:
index index.html index.htm index.php
to the nginx.conf file. Unfortunately, it appears to have no effect.
Any tips on how I can go about troubleshooting this or other ideas to try?
EDIT: based on comments and first answer, I have updated my /etc/nginx
EDIT #2: Reverted to the default nginx.conf file and added #Mason Stedman's code in his answer below to /etc/nginx/sites-enabled/default. Also, used the following tutorial (through step 7) to set up the stack after re-flashing raspian stretch:
https://linoxide.com/debian/install-nextcloud-10-nginx-debian-8/
For completeness, my /etc/nginx/sites-enabled/default file is below. For the server name, I had no idea what to put in, so I used the static IP address I assigned to it on my network (I'm not exposing this to the internet, BTW):
server {
listen 80;
listen [::]:80;
server_name 192.168.xx.xx;
access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;
root /var/www/;
index index.php index.html;
location / {
try_files \$uri \$uri/ /index.php?\$query_string;
}
location ~ \.php$ {
include snippets/fastcgi-php.conf;
fastcgi_pass unix:/run/php/php7.0-fpm.sock;
}
}

Answer 1

Try adding this to your nginx config:
Edit: Here is an example of the full thing you will need to put in there to work. I can edit again if you need SSH support, or a more comprehensive example, but this example will work on just about any configuration.
server {
listen 80;
listen [::]:80;
server_name site.com www.site.com;
access_log /var/log/nginx/site.com.access.log;
error_log /var/log/nginx/site.com.error.log;
root /var/www/site.com/htdocs/;
index index.php index.html;
location / {
try_files \$uri \$uri/ /index.php?\$query_string;
}
location ~ \.php$ {
include snippets/fastcgi-php.conf;
fastcgi_pass unix:/run/php/php7.0-fpm.sock;
}
}
You need to send php files to a parser. You can change the version in that to the version of php you wanna use.