chidan

В локкйшене прописываете location /api/mapapi/ и проксипасс до вашего апстрима . По необходимости добавляете кастомные заголовки. Посмотрите статью kestrel on nginx там описано подробно, но это действует для любых связок

Конфиг для nginx c бэкендом apache, проксированием net core api, и vue SPA

server {
        server_name test.com;
        ssl_certificate "/var/www/httpd-cert/www-root/test_com_le2.crtca";
        ssl_certificate_key "/var/www/httpd-cert/www-root/test_com_le2.key";
        ssl_ciphers EECDH:+AES256:-3DES:RSA+AES:!NULL:!RC4;
        ssl_prefer_server_ciphers on;
        ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
        ssl_dhparam /etc/ssl/certs/dhparam4096.pem;
        charset off;
        index index.php index.html;
        disable_symlinks if_not_owner from=$root_path;
        include /etc/nginx/vhosts-includes/*.conf;
        include /etc/nginx/vhosts-resources/test_com/*.conf;
        access_log /var/www/httpd-logs/test_com.access.log;
        error_log /var/www/httpd-logs/test_com.error.log notice;
        ssi on;
        set $root_path /var/www/www-root/data/www/test_com/public;
        root $root_path;
        location / {
                location ~ [^/]\.ph(p\d*|tml)$ {
                        try_files /does_not_exists @fallback;
                }
                location ~* ^.+\.(jpg|jpeg|gif|png|svg|js|css|mp3|ogg|mpe?g|avi|                                                                                                                                                                                                                                             zip|gz|bz2?|rar|swf)$ {
                        try_files $uri $uri/ @fallback;
                }
                location / {
                        try_files /does_not_exists @fallback;
                }
        }
        # тут хранится статика SPA  
        location /mks/ {
                       root /var/www/www-root/data/www/test_com;
                }
         # Прокси для api
        location /api/mapinfo/ {
            proxy_pass         http://localhost:5010/api/mapinfo;
            proxy_http_version 1.1;
            proxy_set_header   Upgrade $http_upgrade;
            proxy_set_header   Connection keep-alive;
            proxy_set_header   Host $host;
            proxy_cache_bypass $http_upgrade;
            proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header   X-Forwarded-Proto $scheme;
        }
        location @fallback {
                proxy_pass http://127.0.0.1:8080;
                proxy_redirect http://127.0.0.1:8080 /;
                proxy_set_header Host $host;
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_set_header X-Forwarded-Proto $scheme;
                proxy_set_header X-Forwarded-Port $server_port;
                access_log off;
        }
        listen 123.123.123.123:443 ssl;
}